In real-time we may come across scenario where depending on the particular group of users we need to show different layout, colors, themes, functionalities and so on. To achieve this there are various ways, maintain the settings for each user in table , maintain the cookies and so on.

 In .net the best way to achieve this is to change master page dynamically where the master pages will have different layout , different look and feel for different users.  This we can achieve by following below mentioned steps.

1.       All the WebPages will be inherited form System.UI.Web.Page base class

2.       In page directive we  have a property to set masterpage file

3.       Once we attach any master page to any child, first all the controls of the master page are instantiated, then child page controls are instantiated

4.       If we want to apply master page in code behind file ,the page’s master page property needs to be applied in Onpreinit method only.

5.       After instantiating controls, child page load will be called first, then the master page will be loaded.

To change master page dynamically we need to follow the below mentioned process/method

1.       Create one separate class file as public, which will inherits System.UI.Web.Page base class

2.       Override the Page base class method onPreinit(), in this method set the master page property of the page, give the name of the master page file which you want to apply

3.       At the end of the onPreinit() method call the base class onpreinit method

4.       Inherit the newly created class in all of your web pages.

5.       To provide the custom master page, we may use cookies, sessions or the values stored from database, it depends on how we want to manage the customization.

Illustration

Private Sub GridView1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles GridView1.Paint

Dim count As Integer = 0

Dim xCordinate As Integer = _

GridView1.GetColumnDisplayRectangle(GridView1.Columns(“column1”).Index, True).X + 11

1. For count = GridView1.FirstDisplayedScrollingRowIndex To (GridView1.FirstDisplayedScrollingRowIndex + 7)

2. If count < GridView1.Rows.Count Then

3. Dim rct As Rectangle = GridView1.GetRowDisplayRectangle(count, True)

4. Dim rct2 As New Rectangle(xCordinate, rct.Y, 26, 25)

5. e.Graphics.DrawImageUnscaledAndClipped(My.Resources.Image1, rct2)

End If

Next

End Sub

Here are the details of steps mentioned above

1. Looping thorough the rows which comes under visible area. Here in the sample code we have 8 rows visible at a time rest are coming under horizontal scroll. So we loop through only those rows starting from “FirstDisplayedScrollingRowIndex “ and paint cell with an added image.

3. Get the rectangle dimension of each row. This is to set the y coordinate of each image we are going to paint manually

4. Get the rectangle dimension of the area under which we want to paint the image.

Here the left coordinate of rct2 is set by taking the X coordinate of the DataGridViewTextBoxColumn under which we are going to paint the image and adding 11 pixels to accommodate the text.

Y coordinate is the Y coordinate of each row

Width and height of rct2 is the dimension of the image we are going to paint

5. “DrawImageUnscaledAndClipped” draws the image without scaling it and clipped by the rectangle passed as a second parameter

Let’s have a look at the TIMEDIFF() function in MySQL:

TIMEDIFF(expr1,expr2) - TIMEDIFF() returns expr1 – expr2 expressed as a time value. expr1 and expr2 are time or date-and-time expressions, but both must be of the same type.

It seems that when TimeDiff is performed on 2 dates that exceed 36 days then a warning is thrown, and the resulting value is always capped to 838.

For example:

select time_format(timediff(‘2009-02-05 00:00:00′,’2009-01-01 00:00:00′),’%H’) as TimeDifference

If you execute the above query MySQL will return 838 instead of returning 840 (35 X 24 = 840).

The reason is precisely because TIME type in MySQL has an upper bound of 838:59:59. TIME values may range from ‘-838:59:59′ to ‘838:59:59′.

By using TIMESTAMPDIFF() function you can get around with this problem.

Let’s have a look at the TIMESTAMPDIFF() function in MySQL:

TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2) – Returns datetime_expr2 - datetime_expr1, where datetime_expr1 and datetime_expr2 are date or datetime expressions. One expression may be a date and the other a datetime; a date value is treated as a datetime having the time part '00:00:00' where necessary. The unit for the result (an integer) is given by the unit argument. The legal values for unit are FRAC_SECOND (microseconds), SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or YEAR.

It is bit confusing timediff and timestampdiff expects the times in opposite order.

Now let’s try timestampdiff() with same dates

select timestampdiff(hour,’2009-01-01 00:00:00′,’2009-02-05 00:00:00′) as TimeDifference

If you execute the above query MySQL will return 840. Even if the difference is more than 840 it will not throw any exceptions or any warning. Hence we can use TIMESTAMPDIFF() function where the difference is more than 838 and can get the output in any of FRAC_SECOND (microseconds), SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or YEAR.

There you have it … I hope you enjoyed this article. Please leave comments / suggestions / questions if you have.

Introduction:

As we know we use to build the connection strings by copying the existing connection string and renaming the DatsourceName,UserName,Password like that but here we will be discussing about how to build the connection string without copy paste.

Approach:

There is a way to build the connection string for any database which DotNet supports.

1.Open a notepad

And save it as somename.udl where udl (Universal Data Link) is the extension the udl files are used to build the connection string we can directly use the udl file to open the connection to the database

2. Then you can find the file with the following icon as shown below

3. Now open this file by double click it will be as shown below

Now select the provider what ever you like from the list and click next in my case I am selecting the Oledb SqlProvider and clicking next

4.Then you can see the screen as below

then we need to provide the server name ,username if you are not using windows authentication and check the allow saving password option for saving the password in the file now select the database to which you need the connection and then click ok.

Note: – You can find the database list if the details provided by you are valid

5. Now the connection string is ready

How to use this:
1.You can directly use the udl file to open the connection and connect to the database but the limitation is it is supported
by oledb Providers only.Sample code

OleDbConnection connection = new OleDbConnection("File Name= D:\\connection.udl");
OleDbCommand command = new OleDbCommand("select * from Cities",connection);
OleDbDataReader reader;
try
{
connection.Open();
reader = command.ExecuteReader();
while (reader.Read())
{
ListBox1.Items.Add(reader["Cities"].ToString());
ListBox2.Items.Add(reader["Cities"].ToString());
}
ListBox1.DataBind();
ListBox2.DataBind();
}
catch (Exception error)
{ }
finally
{
connection.Close();
}

2. You can directly get the connection string from the file and we can use directly in our code
Open the file with notepad as shown below

And there you can find your connection string like this

[oledb]
; Everything after this line is an OLE DB initstring

Provider=SQLOLEDB.1;Password=mypassword;Persist Security Info=True;User ID=username;Initial
Catalog=datbasename;Data Source=servername

Conclusion: -

By using this udl files we can build connection string for any type of database easily.

As we know we can bind the controls to our page (aspx) in 2 ways
1. Statically :- Binding the controls while Designing
2. Dynamically :- Binding the controls at runtime

Everyone know how to bind statically but there may be some cases where we need to bind the control dynamically .One of those cases is when our controls are keep on changing like I have a registration site in which the control type may keep on changing then I may need to go for binding the controls dynamically .

Approach:

For binding the controls I need the data what are the controls I want to bind and what is the id to be given and what are the properties to be provided etc.,

This can be provided by 2 ways

1. Using database (This is my approach)
2. Using Xml file

I am creating one example (registration Page) where I am getting the data from the database as a table and based on this table I will be binding my controls to the page as we can see below

My Controls Data from database

ControlText : - Text to be Displayed

ControlType :-

1 – TextBox Control
2 – DropDown Control
3 – DateTime Control
4 – Buttom Control

MaxLength:- Defining the maximum length for textbox

Manditory :- Based On this we will be binding the required field validation

HelpText :- This is used to bind as ToolTip for the control

Source :- Use for binding data source for dropdown controls

Page in which all the controls are generated dynamically

Implementation:

As we know all the server control are under System.Web.UI.WebControls namespace

I will be getting the tabel into a dataset for suppose the name is controlsDataSet

///
/// Method usd to bind the controls
///
///
private void BuldControls(DataSet controlsDataSet)
{
Table table = new Table();
table.Style.Add("align", "center");

// Looping the dataset and get the values
foreach (DataRow datarow in controlsDataSet.Tables[0].Rows)
{
int controlType =
Convert.ToInt32(datarow["ControlType"].ToString());
string controlText = datarow ["ControlText"].ToString();

TableRow newRow = new TableRow();
TableCell textCell = new TableCell();

// Binding the text
textCell.Text = controlText;
newRow.Cells.Add(textCell);

TableCell valueCell = new TableCell();
Control[] cntrlCollection=new Control[4];

// Checking the control Type
switch(controlType)
{
// If TextBox
case 1:
cntrlCollection = this.BindTextBox(control);
break;

// If DropDown
case 2:
cntrlCollection = this.BindDropDown(control);
break;

// If DateTime
case 3:
cntrlCollection = this.BindDateTime(control);
break;

// If Button
case 4:
cntrlCollection = this.BindButton(control);
break;

}

// Adding th controls to the table cell
foreach (Control cntrl in cntrlCollection)
{
if (cntrl != null)
{
valueCell.Controls.Add(cntrl);
}
}

newRow.Cells.Add(valueCell);
table.Rows.Add(newRow);
}

// Adding the table to the main panel
this.pnlControls.Controls.Add(table);
}

Creating controls dynamically is not a big matter but we have bind in such a way that when we are retriving it should not be a problem so we need to give the ids of the controls as below

///
/// Method to bind the DropDown
///
///
///
private Control[] BindTextBox(DataRow datarow)
{
// Retriving the values from the datarow
int controlId = Convert.ToInt32(datarow["Id"].ToString());
int length = Convert.ToInt32(datarow["MaxLengh"].ToString());
bool required =
Convert.ToBoolean(datarow["Manditory"].ToString());
string helpText = datarow["HelpText"].ToString();
string controlText = datarow["ControlText"].ToString();

// Creating the controls array
Control[] controls = new Control[4];

// creating the textbox
TextBox textbox = new TextBox();
textbox.ID = string.Concat(“txt”, controlId);
textbox.ToolTip = helpText;

// Checking the length
if (length != 0)
{
textbox.MaxLength = length;
}

// Adding the textbox to the control array
controls[0] = textbox;

// Checking id manditory
if (required)
{
controls[1] = this.BindRequiredvalidator(controlId,
textbox.ID, controlText);
}
return controls;
}

Suppose I am bind for the name column the textbox id becomes like this
“txt_1” and while saving also we can save accordingly.

So this is the way how to bind the controls and now coming to validation controls (I and using the controls provided my the VS).I am showing you a example where I am bind a validation control to textbox as shown below

private RequiredFieldValidator BindRequiredvalidator(int Id, string
controlId, string controlText)
{
RequiredFieldValidator requiredFieldValidator = new
RequiredFieldValidator();
requiredFieldValidator.ID = string.Concat(“rfv”, Id);
requiredFieldValidator.ControlToValidate = controlId;
requiredFieldValidator.SetFocusOnError = true;
requiredFieldValidator.ErrorMessage = string.Concat(“Enter “,
controlText);
return requiredFieldValidator;

}

For this method I will be passing the Id , ControlId (Like textbox control id) which need to be validated ,controlText used for error messaeges

And after doing all these we can see the paeg with validation controls like this

With Validation controls

Advantages over binding controls statically:

1. Suppose we need to add 10 controls and we are using those statically but now I need to change my control type like a textbox to be changed to dropdown then I need to change all my code once again but this easier while binding controls dynamically.
2. Can bind any validation to any control dynamically.

The use cases and class diagrams are very useful in order to plan and designing any project. Before understanding use cases and diagrams we need to know regarding UML.

UML can be abbreviated as Unified Modeling Language, which is used in order to provide a common modeling for various
problems/projects which are platform independent, technology independent and support purely object oriented programming languages.

The use cases can be defined in simple word as scenario in which the given problem solution will be used and what are all the cases that may arise while using the project/solution.

The use cases helps the system design and development easier by providing the necessary and mandatory cases that are the users of any project.  The use cases can be represented by using standard notations.  The following are the notations which are used in order derive the use cases most commonly.

In order to understand the use cases in better way, let me explain an example, consider the video conference system as a problem/project, in order to implement this project first I need to gather the information from user/client properly once the required information is gathered by using any of the information gathering techniques, I can start on writing the use cases for video conference system.

The use cases are formed or designed by considering the main functional requirements of the system not mapped one-to-one and it shows what behavior the actor can expect and not how the system will work to provide the service.

In order to write the use cases we need to know two things properly in use cases

1.  Actor,the external agent who will make use of the system

2. Service provided by the System

In the video conference system the actors are the persons who will make use of the system by connecting to the system, and the services provided by the system are login authentication, video conferencing, video recording, text messaging.  These are all the main functional requirements which are identified in order to develop the video conferencing system.  The following are the different use cases those can be derived or drawn by considering the video conferencing system and the services provided by the system.

The following are the example/illustrative use case diagrams with respect to web based video conferencing system, which is used for video conferencing over the internet.

The use case diagrams does have extension, aggregation and interface concept those can be represented pictorially as above.

Class Diagrams

                The class diagrams are diagrams which are used in order to represent the classes used or to be used in any solution
implementation using notations.  The class diagrams makes the understandability of the project flow and the pictorially represents the different classes used and how they were connected to each other  and which are all the classes that depends on the other classes can be represented.

The class diagram can be represented by following notation and it does mainly have 3 parts first part is the name of the class, the second box or part is declaration of members or variables which are used in the class, the third part/box will be list of all the methods which are implemented in the class in order to perform the operations on class data members.

The following notations are used in drawing class diagrams.

The Class diagrams can be used to represent all the available variants of classes in Object oriented languages.

The example class diagram used in web based video conferencing system.

In this diagram, as we can see the class is of type public and class name is enter_002dconf2_jsp used in web based video conferencing system, the member of the class is _dependants of  type Vector and access mode is private.

The two methods are defined of type public in order to perform the required operation, the getDependants() ,
method will get all the necessary dependents needed to start the video conferencing service, and the second method will _jspService() will start the service and write the required information on to the browser, if the required dependents are present then the client application will run through which the user can able to perform video conferencing, if not then the
necessary information will be written on to the browser.

IPV4 vs IPV6:

Problem Scenario: I was involved in developing an windows application which suppose to work on    windows 2003, windows xp or earlier version. But at the time of deploying the application to the one machine which is using Windows Vista as OS, my application crashes. It is not getting started. But the same application is working in other Test system having Vista OS.

Solution: After digging into the code I finally found the problem. Before starting, the application it collects few system information’s like Host Name, Host IP address etc and saves into the database. And Client Vista system is using IPV6 format address where as the application is expecting IPV4 address format. Here I came across the need to fetch the IPV4 address if some system is using IPV6 address.

What are IPV4 and IPV6?

IPv6 stands for Internet Protocol version 6 which is the next-generation Internet Layer protocol for packet-switched internetworks and the Internet. IPv4 is currently^[update] the dominant Internet Protocol version, and was the first to receive widespread use. In December 1998, the Internet Engineering Task Force (IETF) designated IPv6 as the successor to version 4 by the publication of a Standards Track specification.

Get Into the problem.

In my application it is expecting IPV4 address format, which can be split into four sections by “.” character and each section represents an integer. On the contrary IPv6 address size is 128 bits and the preferred IPv6 address representation is: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx where each x is a hexadecimal digit representing 4 bits. IPv6 addresses range from 0000:0000:0000:0000:0000:0000:0000:0000 to ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff. So we need to fetch list of all ip addresses on the host system and fetch the V4 representation of IP address.

Code to fetch the V4 representation of IP address:

Dim IP4Address As String = String.Empty

For Each IPA As IPAddress In Dns.GetHostAddresses(Dns.GetHostName())

If IPA.AddressFamily.ToString() = “InterNetwork” Then

IP4Address = IPA.ToString()

Exit For

End If

Next

The GetHostAddresses() method queries a DNS server for the IP addresses associated with a host name

For V4 comes under address family “InterNetwork”.

Also we can serve the same purpose by using Dns. GetHostByName() method but it advisable to GetHostEntry() or GetHostAddresses() method as GetHostByName() become obsolete. Also we can use “IsIPv6SiteLocal”, “IsIPv6LinkLocal” properties of IPAddress to determine if the current address is V6 format.

Introduction

· Menus make it easy to access the functionality and take less space and make your application look more organized.

· Menus contain top – level items and drop – down items.

o Top – level items: all visible items are top-level menus

o Drop – down items: non – visible items are dropdown menus and also call it as child menus of a top – level menu.

Classes required to create a Menu

1. MenuStrip:

· This control is like a container will hold all the top – level menus going to be created.

· This control will be available under “System.Windows.Forms” namespace.

Decalration of a MenuStrip control

Import the namespace – using System.Windows.Forms

// Declare the menustrip object.

MenuStrip menuItems = new MenuStrip();

2. ToolStripMenuItem :

· This class is used to create menu items like top – level or drop – down menus going to be created.

· It can also represent a submenu of another ToolStripMenuItem object. ToolStripMenuItem objects are viewed by the user, whereas a MenuStrip object simply establishes a container where menu items appear.

· This class will be available under “System.Windows.Forms” namespace.

Decalration of a MenuItem class

Menu can be created using a Text or Image or both.

// Take a ToolStripMenuItem to add the menu item with string.

ToolStripMenuItem menuItem = new ToolStripMenuItem(“File”);

Or

// Take a ToolStripMenuItem to add the menu item with Image.

ToolStripMenuItem menuItem = new ToolStripMenuItem(new Bitmap(“path of the image to load”));

Or

// Take a ToolStripMenuItem to add the menu item with Strng and Image.

ToolStripMenuItem menuItem = new ToolStripMenuItem((“File”, new Bitmap(“path of the image to load”));

These are the main classes to create any kind of menu.

Using this information will know how to create dynamic menus.

Program: Going to create dynamic simple menus

Output: looks like this

File Edit Help - Top – level menus

New Copy AboutMe - drop – down menus

Open Cut ContactUs

Exit Pate Help

Step-By-Step code explanation to create a dynamic menu

1. Define menus required.

Note: There will be so many ways to approach declaring the menu items but here I used by taking dictionary object.

// Create Main menu and child menus in a ditcionary object as key pair values.

Dictionary<string, string[]> displayMenus = new Dictionary<string, string[]>();

// Define the child menus based on the each main menu on the basis of key.

displayMenus.Add(“File”, new string[] { “New”, “Open”, “Exit” });

displayMenus.Add(“Edit”, new string[] { “Copy”, “Cut”, “Paste” });

displayMenus.Add(“Help”, new string[] { “AboutMe”, “ContactUs”, “Help” });

2. Write a function to create menus by taking the dictionary object as parameter.

/// <summary>

/// This method will create a menu based on the menus

/// and it’s submenus defined.

/// </summary>

/// <param name=”displayMenus”>

/// Menus and it’s submenus in a dictioanry object

/// </param>

/// <returns>

/// Returns a collection of a toolstripmennu items.

/// </returns>

private List<ToolStripMenuItem> CreateMenu(Dictionary<string, string[]> displayMenus)

{

// Declare ToolStripMenuItem object.

List<ToolStripMenuItem> menuItems = new List<ToolStripMenuItem>();

// Loop through all main menus.

foreach (KeyValuePair<string, string[]> menu in displayMenus)

{

// Take a ToolStripMenuItem to add the menu item.

ToolStripMenuItem menuItem = new ToolStripMenuItem(menu.Key);

// Set a name to the menu.

menuItem.Name = menu.Key;

// Create child menu items for a menu item.

this.CreateChildMenus(menuItem, menu.Value);

switch (menu.Key)

{

case “File”:

case “Edit”:

// This is by default.

// menuItem.Alignment = ToolStripItemAlignment.Left;

break;

case “Help”:

menuItem.Alignment = ToolStripItemAlignment.Right;

break;

}

// Add each menu item to the menu strip item.

menuItems.Add(menuItem);

}

return menuItems;

}

3. Write a function to create child menus by taking the parent menu and the child menus going to be created.

/// <summary>

/// Thsi method will create a child menus of a menu item.

/// </summary>

/// <param name=”parentMenuToAddChildMenus”>

/// Parent menu item to add child menu items.

/// </param>

/// <param name=”childMenus”>

/// Child menu items going to be created.

/// </param>

private void CreateChildMenus(ToolStripMenuItem parentMenuToAddChildMenus, string[] childMenus)

{

// Loop through all child menus.

foreach (string childMenu in childMenus)

{

// Take a ToolStripMenuItem to add the menu item.

ToolStripMenuItem childMenuItem = new ToolStripMenuItem(childMenu);

// Set a name to the menu.

childMenuItem.Name = childMenu;

// Hnadle the event for the menu created.

childMenuItem.Click += new EventHandler(ChildMenu_Click);

// Add each child menu to its parent menu item.

parentMenuToAddChildMenus.DropDown.Items.Add(childMenuItem);

}

}

4. Write an event handler common to all the menu items.

/// <summary>

/// This method will handle the click event for each menu.

/// </summary>

/// <param name=”sender”>Tool strip menu item.</param>

/// <param name=”e”>Event args.</param>

private void ChildMenu_Click(object sender, EventArgs e)

{

ToolStripMenuItem sourceMenuItem = (ToolStripMenuItem)sender;

string selectedMenu = string.Empty;

// Selected menu item

switch (sourceMenuItem.Name)

{

case “New”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “Open”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “Exit”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “Edit”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “Copy”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “Paste”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “AboutMe”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “ContactUs”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

case “Help”:

// Required statements here.

selectedMenu = sourceMenuItem.Text;

break;

}

if (!string.IsNullOrEmpty(selectedMenu))

{

MessageBox.Show(string.Concat(

selectedMenu,

” feature is under development “));

}

}

5. add the created menu items collection to the MenuStrip object

Conclusion:

· This is the procedure to create dynamic menus in windows application.

· If you want to create your custom type dynamic menus then modify the code according to your needs in a dictionary object as defined in step1.

Note: This is just a sample code to guide you how a menu can be created.

Download: dynamicmenuscreation.zip

Embedding forms inside a form in windows application:

Problem Scenario:

Let me first give a brief introduction of the problem so that we can understand better about the context of the solution.

In one of my project, I need to wrap up an old application with the new features and functionalities. But the problem I faced is, in every form, customer wants two new sections to be added and those two sections will remain fixed for all the forms.

Solution:

The options I left with is either to edit each form and add those two section to each form or we can have a MDI form or a simple form and divide it into three sections.

Top and side left portion will be fixed and in bottom right portion, different forms will be loaded and unloaded as per the triggered events from other two sections. Also we need to make right bottom corner scrollable.

We adopt the second solution and there by came across the need for “Embedding a form inside a form”.

The goal is to achive an effect like we have with Master page scenario in asp 2.0. where we can have common fixed portion appearing for all pages. These are useful for many scenarios such as having side menu bar etc. To achieve the goal I chose MDI form having divided into sections by number of panels (in my case it’s three) and load the user controls for the portions which are going to be fixed. According to the triggered events on those user controls we can load unload forms on the third panel.

Started With:

We can embed form within another form or within a MDI form. Both the approach is basically same except few differences. But let understand the difference between adding a control and a form to another form. Control can be added at design time by drag drop or at run time using Me.controls.add() method. But in case of embedding a form within a form we have to do it in run time, but before that we need to have a container control like panel, as we can not just use Me.controls.add. In case of MDI form we can use Controls. Add () method but that wont server our purpose.

Steps to embed form within an MDI form

As discussed above let say we have a MDI form with name “frmMDI” which has three panels: – pnl1, pnl2 and pnl3.

To add user controls to the panels we can use

Pnl1.Controls.Add (instance of user control)

But to add form to panel let say pnl3 below is the steps need to follow

Dim sampleOne As New frmSampleOne

sampleOne.MdiParent = frmMDI

sampleOne.TopLevel = False

sampleOne.FormBorderStyle = Windows.Forms.FormBorderStyle.None

sampleOne.AutoScroll = True

sampleOne.Dock = DockStyle.Fill frmMDI.pnlFrm.Controls.Add(GeneticHx)

sampleOne.Show()

sampleOne.WindowState = FormWindowState.Normal

lets discuss the steps:

1. First need to instantiate the form

2. Set the Mdi parent to the frmMDI so that you can use “ActiveMdiChild” fi needed

3. We need to set the TopLevel property of the form to false. By default the TopLevel property of the form is true. This property indicates whether to display the form as a top-level window. A top-level form is a window that has no parent form, or whose parent form is the desktop window. Top-level windows are typically used as the main form in an application. So if we do not set the TopLevel property to false it will throw exception as the form is going to add under a container control like Panel or MDI form.

4. Set FormBorderStyle to none to remove the upper action bar.

5. Set the AutoScroll to true. This is needed to for scrolling to appear. Here we need to understand that scrolling appears on the form which is getting added not on the panel. Here the AutoScroll property for the form means that if the form exceeds the size of its parent control (here pnl3) scrolling appears.

6. Set the Dock property “fill” so that it can acquire the whole space under the panel

7. Add the form object into the panel by Controls.Add() method

8. Invoke the show () methode on the form object to make the form loaded.

9. Set the WindowState property to Normal. This very important for the scrolling to come. If we set the WindowState to maximum, scrolling will not come for form .

Also one point is worth mentionable here is that if you are adding a form and that form itself has one or more panels then make sure that the Dock property of those panel set to None. if not scrolling will not appear for that form.

As we have now finished with adding form under a panel now let’s see how we can load and unload forms and invoking events on those forms from out side panel. Let say as per our example on click of a button on pnl2 I need to close the form under pnl3 if any and load frmSampleTwo in that panel.

For the above mentioned situation first we need to access the form instance in the panel.

Dim sampleOne As frmSampleOne

Dim ctl As New Control

If frmMDI.pnl3.Controls.Find(“frmSampleOne”, True).Length > 0 Then

ctl = frmMDI.pnl3.Controls.Find((“frmSampleOne”, True)(0)

sampleOne = CType(ctl, Form)

Follow the steps as mentioned above for adding new form (frmSampleTwo) in pnl3

sampleOne.close()

End If

As the above code shows once we get the instance of the form under pnl3 we can invoke any events and methods having public modifier.

It’s always good to load the next form before closing the existing one to avoid flickering effect. That’s the reason we load frmSampleTwo before invoking close () method on sampleOne.

By applying above concept we can divide a form into sections and can load more than one form under each section.

]]> http://blogs.circlesource.com/2009/01/20/embedding-forms-inside-a-form-in-windows-application/feed/ 0 http://blogs.circlesource.com/2009/01/20/velocity-usages-and-its-advantages/ http://blogs.circlesource.com/2009/01/20/velocity-usages-and-its-advantages/#comments Tue, 20 Jan 2009 01:22:47 +0000 srinivas.reddy http://blogs.circlesource.com/?p=114

Using Velocity and its advantages

It’s a distributed system. Velocity provides highly scalable distributed caching environment for Microsoft .net framework. By using this we can store frequently used data for faster access and also avoids unnecessary calls to the database. Velocity also supports optimistic and pessimistic locking as well as automatic load balancing.

We can use velocity either in windows application or web application.

Microsoft provides velocity in the form of a cluster. In this section we look at what are all those useful elements having cluster, how cluster works and some useful programming with velocity.

In velocity one of the major element is named cache by using this we can store logical grouping of data like a database. A cluster can have any no of named caches. We can use one or more named caches in our applications. We can directly store objects in a cache without creating named cache. In this case those objects are stored in default named cache of the cluster.

We can create or delete the cache using velocity administration tool

Example: Create Cache CacheSample

Delete Cache CacheSample

Here CacheSample is the name of the cache

Another major (optional) element is regions. Actually regions are logical grouping of objects in a named cache like database tables. Regions provide additional searching capabilities. We can create any no of regions on a named cache. Regions are not possible to create using administration tool. We must be creating a region using explicitly run time using application.

We can also check what are all those regions inside the caches and regions available in a cluster using this below command

Example: List Host CacheSample

Velocity allows blindly any time of CLR serialized object in the form of key value pairs

Regions can store any no of objects but depend on size of cluster installation. Anyway once we are added object in a cache that object resides in a cache including version, time to live (TTL) and tags.

The below example describes how to add item to the cache and get the item from cache.

Step 1 First run velocity setup and then references the following .dll from the Program Files\Microsoft Distributed Cache folder: CacheBaseLibrary.dll, ClientLibrary.dll, FabricCommon.dll, CASBase.dll, and CASClient.dll to visual studio .net project.

Step 2 We also need to add the below configuration information to app.Config file or Web.Config file.

Example:

<configSections>

<section name=“dcacheClient“ type=“System.Configuration.IgnoreSectionHandler“ allowLocation=“true“ allowDefinition=“Everywhere“ />

<section name=“fabric“ type=“System.Fabric.Common.ConfigFile, FabricCommon“ allowLocation=“true“ allowDefinition=“Everywhere“ />

</configSections>

<dcacheClient deployment=“simple“ localCache=“false“>

<hosts>

<!–List of hosts –>

<host name=“NameOfCacheServerSystem” cachePort=“22233“ cacheHostName=“DistributedCacheService“ />

</hosts>

</dcacheClient>

<fabric>

<section name=“logging“ path=“”>

<collection name=“sinks“ collectionType=“list“>

<customType className=“System.Fabric.Common.EventLogger,FabricCommon“ sinkName=“System.Fabric.Common.ConsoleSink,FabricCommon“ sinkParam=“” defaultLevel=“-1“ />

<customType className=“System.Fabric.Common.EventLogger,FabricCommon“ sinkName=“System.Fabric.Common.FileEventSink,FabricCommon“ sinkParam=“CacheClientLog“ defaultLevel=“1“ />

<customType className=“System.Fabric.Common.EventLogger,FabricCommon“ sinkName=“System.Data.Caching.ETWSink, CacheBaseLibrary“ sinkParam=“” defaultLevel=“-1“ />

</collection>

</section>

</fabric>

Step 3 Needs to create a named cache from velocity administration tool

Create Cache CacheSample

Here ‘CacheSample’ is the named cache.

Step 4 Create the instance of the cache factory class and get the named cache from that instance.

CacheFactory cacheFactory = new CacheFactory();

Cache cache = cacheFactory.GetCache(“CacheSample “);

Step 5 create the region

cache.CreateRegion(“SampleRegion”,true);

Step 6 Add the item(object) to the region

We can add any CLR serialized object by using Add and Put methods.The main difference between Add and Put is Add will throw an error if given key is already exists but put will not throw any exception if the given key is already exists its replace with newer one. On the other hand if the given key is does not exist the object will be added to the cluster.

ADD Method

// Name of the region in a named cache

// Key for uniquely identify the cache object

// Cached object(in this case ds)

// Searchable information

// Version information

// Time to alive in cache interms of minutes

cache.Add(“SampleRegion”, “Id”, ds, searchInfo,15);

Put Method

// Name of the region in a named cache

// Key for uniquely identify the cache object

// Cached object(in this case ds)

// Searchable information

// Version information

// Time to alive in cache interms of minutes

cache.Put(“SampleRegion”, “Id”, ds, searchInfo, null, 15);

Get Method

// Name of the region in a named cache

// Key for uniquely identify the cache object

// It returns a cache Item Object.

// That need to cast into appropriate type

CacheItem item = cache.GetCacheItem(“SampleRegion”, “Id”)

Remove the item from Cache

Remove method deletes object with specified key from the cache.

1. Remove the object with specified key from cache

// Unique key associated with the object.

cache.Remove(“Id”);

2. Removes the Object with specified key from specified region

// Name of the region, cannot be null.

// Unique key associated with the object.

cache.Remove(“SampleRegion”, “Id”);

3. Drop the region with the specified name.

// Name of the region, cannot be null.

// If it returns true then successful other wise returns false.

Cache.RemoveRegion(string region);