I have often read a common question in forum posts of how to set
the values of a User Control from a parent page in ASP.NET but no one
has provided the proper solution so by considering the preceding
requirements I have decided to write this article to provide the
step-by-step solution to create a User Control. So let us start creating
an application so beginners can also understand.
What User Control Properties Are
For more details of how to create a User Control please refer to my previous article:
So let us learn practically about User Controls in depth.
Now open the design mode and add the two textboxes. After adding it, the User Control source code will look as follows:
Now we need to add the User Control into an .aspx page to use
it. So let us add the Default.aspx page by right-clicking on the
project in the Solution Explorer. After adding the .aspx page the
Solution Explorer will look such as follows:
Step 1: Create Web Application
Now let us create the sample web application as follows:
- "Start" - "All Programs" - "Microsoft Visual Studio 2010".
- "File" - "New WebSite" - "C#" - "Empty WebSite" (to avoid adding a master page).
- Provide the web site a name such as "PropertiesinUsercontrol" or another as you wish and specify the location.
- Then right-click on the project in the Solution Explorer then select "Add New Item" then select Web User Control template as in the following:
Now open the design mode and add the two textboxes. After adding it, the User Control source code will look as follows:
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="student.ascx.cs" Inherits="student" %> <h3>This is User Contro1 </h3> <table> <tr> <td>Name</td> <td> <asp:TextBox ID="txtName" runat="server"></asp:TextBox> </td> </tr> <tr> <td>City</td> <td><asp:TextBox ID="txtcity" runat="server"></asp:TextBox></td> </tr>
Step 3: Create Properties in User Control
Write the following code in the student.ascx.cs file to create the properties as:
public string Name { get { return txtName.Text; } set { txtName.Text = value; } } public string City { get { return txtcity.Text; } set { txtcity.Text = value; } }
In the
preceding code we are setting the values to the User Control textboxes,
now after creating the properties the student.ascx class file will look
as in the following:
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class student : System.Web.UI.UserControl { protected void Page_Load(object sender, EventArgs e) { } public string Name { get { return txtName.Text; } set { txtName.Text = value; } } public string City { get { return txtcity.Text; } set { txtcity.Text = value; } } }
Now we are done
with the properties. Let us use it in an .aspx page. As already
discussed in the preceding, a User Control does not run directly on its
own. To render a User Control you must use it in an .aspx page, now let
us add the User Control to the .aspx page.
Step 4: Adding User Control into .aspx page
Step 5: Register the User Control on .aspx page
To use a User Control in an .aspx we need to register it using the
Register page directive, the register page directive has the following
properties:
<%@ Register Src="~/student.ascx" TagPrefix="uc" TagName="Student" %>
Now
open the default.aspx page and drag and drop two text boxes, one button
and also add a control to the .aspx page form the section. After adding
the Default.aspx the source code will be such as follows:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <%@ Register Src="~/student.ascx" TagPrefix="uc" TagName="Student" %> <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title>Article by Vithal Wadje</title> </head> <body bgcolor="blue"> <form id="form2" runat="server"> <div style="color: White;"> <h4> Article for C#Corner </h4> <table> <tr> <td>Name</td> <td> <asp:TextBox ID="txtName" runat="server"></asp:TextBox> </td> </tr> <tr> <td>City</td> <td><asp:TextBox ID="txtcity" runat="server"></asp:TextBox></td> </tr> <tr> <td></td> <td> </td> </tr> <tr> <td></td> <td> <asp:Button ID="txtSave" runat="server" Text="Save" onclick="txtSave_Click" /> </td> </tr> </table><br /> <uc:Student ID="studentcontrol" runat="server" /> </div> </form> </body> </html>
Now switch to design mode and it will look as in the following:
In the preceding UI, on the save button we will pass the values to
the user text box controls and I will show it in the User Control text
box, now let us see how properties will look, its similar to any
standard TextBox control as:
Step 6: Set the values to User Control from .aspx page using User Control properties
Now in the preceding control you have seen that the properties of
the User Control we have created are shown the same as standard contols.
We can also create properties to set the height and width and so on in a
similar manner. Double-click on the Save button and write the following
code in the Default.aspx.cs file to set the values:
protected void txtSave_Click(object sender, EventArgs e) { //setting the values to the User Control properties studentcontrol.Name = txtName.Text; studentcontrol.City = txtcity.Text; }
Now the entire code of the Default.aspx.cs class file will look as in the following:
using System; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void txtSave_Click(object sender, EventArgs e) { //setting the values to the User Control properties studentcontrol.Name = txtName.Text; studentcontrol.City = txtcity.Text; } }
Now run the application, the UI will look as in the following:
Now enter the name and city into the preceding two text boxes and
click on the save button. The output will be shown in the User Control
text boxes as follows:
Now you have seen that we do not have any code in the .ascx page
that is in the User Control but still the output is shown because all
the logic is written in the User default.aspx page and the values are
assigned using properties to the User Control from the parent page.
Summary
From all the preceding examples you have learned how to use the
properties in a User Control to assign the values. I hope this article
is useful for all readers, if you have a suggestion then please contact
me.
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