User Control: User Control is the custom, reusable
controls. User Controls offers a way to partition and reuse User
Interface (UI) functionality across ASP.NET Applications.
Advantages of User Control:
• Code Reuse.
• Cache the output of the control independently using technique called fragment caching. This will improve performance if used appropriately.
• Can program against any properties declared in the control, just like ASP.NET web controls.
Disadvantages of User Control:
• User Controls can be instantiated in the pages that resides in the same web application. If you want to use across applications, you need to place same .ascx control in each application.
• Can't hide code of user controls like server controls by compiling into an assembly.
Adding User Controls to an WebForms Page:
At the top of the .aspx page, add the below line above tag.
<!--Register TagPrefix="Test" TagName="TestControl" Src="Test.ascx"-->
This directive registers the control so that it can be recognized when the page is processed. TagPrefix determines the unique namespace of the control, TagName is the name of the user control and Src is the path of the user control.
If your user control is registered into Web.Config then there is no need to register on each page.
Declare user controls like
<testcontrol id="TestControl" runat="Server">>
Accessing and Setting User Controls Values in the .aspx Page:
User can access and set the values of the User Control from .aspx page through properties, using JavaScript and in code-behind of aspx page. The details of it are shown below
1. Using Properties:If the test.ascx control has two textboxes and submit button. You can access the values of the textboxes in the control from an .aspx page by declaring public property in the .ascx page.
Public Property FirstName() As String
Get
Return txtFirstName.Text
End Get
Set
txtFirstName.Text = Value
End Set
End Property
In .aspx page,you can access FirstName using "TestControl.FirstName" & You can set the FirstName of the control from aspx page using TestControl.FirstName = "Suzzanne"
2. Using Javascript: You can set the values of the controls declared in the .ascx page by
Private document.forms(0)("TestControl:txtFirstName").value ="Suzzanne"
You can get the values of the controls declared in the .ascx page by
Private document.forms(0)("TestControl:txtFirstName").value
3. In ASPX code behind file:
Private objTestControl As TestControl = CType(Page.FindControl("TestControl"), TestControl)
Private objTextBox As TextBox = objTestControl.FindControl("txtFirstName")Private strFirstName As String = objTextBox.Text
Advantages of User Control:
• Code Reuse.
• Cache the output of the control independently using technique called fragment caching. This will improve performance if used appropriately.
• Can program against any properties declared in the control, just like ASP.NET web controls.
Disadvantages of User Control:
• User Controls can be instantiated in the pages that resides in the same web application. If you want to use across applications, you need to place same .ascx control in each application.
• Can't hide code of user controls like server controls by compiling into an assembly.
Adding User Controls to an WebForms Page:
At the top of the .aspx page, add the below line above tag.
<!--Register TagPrefix="Test" TagName="TestControl" Src="Test.ascx"-->
This directive registers the control so that it can be recognized when the page is processed. TagPrefix determines the unique namespace of the control, TagName is the name of the user control and Src is the path of the user control.
If your user control is registered into Web.Config then there is no need to register on each page.
Declare user controls like
<testcontrol id="TestControl" runat="Server">>
Accessing and Setting User Controls Values in the .aspx Page:
User can access and set the values of the User Control from .aspx page through properties, using JavaScript and in code-behind of aspx page. The details of it are shown below
1. Using Properties:If the test.ascx control has two textboxes and submit button. You can access the values of the textboxes in the control from an .aspx page by declaring public property in the .ascx page.
Public Property FirstName() As String
Get
Return txtFirstName.Text
End Get
Set
txtFirstName.Text = Value
End Set
End Property
In .aspx page,you can access FirstName using "TestControl.FirstName" & You can set the FirstName of the control from aspx page using TestControl.FirstName = "Suzzanne"
2. Using Javascript: You can set the values of the controls declared in the .ascx page by
Private document.forms(0)("TestControl:txtFirstName").value ="Suzzanne"
You can get the values of the controls declared in the .ascx page by
Private document.forms(0)("TestControl:txtFirstName").value
3. In ASPX code behind file:
Private objTestControl As TestControl = CType(Page.FindControl("TestControl"), TestControl)
Private objTextBox As TextBox = objTestControl.FindControl("txtFirstName")Private strFirstName As String = objTextBox.Text
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