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How to use CheckBox control in asp.net c#


CheckBox Server Control



The CheckBox is an asp.net web server control. A CheckBox allows the website visitor to select (check) a true or false condition. So the CheckBox control creates a CheckBox on the web forms page which allow the user to switch between a true or false state. CheckBox Text property creates a caption for it. We can left or right-align the caption by using the CheckBox TextAlign property.




The CheckBox control has many properties that help us to change looks and styles such as ForeColor, BorderColor, BackColor, BorderStyle, BorderWidth, CssClass, EnableTheming, Font, Height, SkinID, ToolTip, Width, etc.




If we want to determine whether CheckBox is checked (selected) then we need to test the CheckBox Checked property. CheckBox AutoPostBack property value true enable automatic posting to the server. CheckBox CheckedChanged event is raised when someone changes the CheckBox true or false state. The .NET developers can write an event handler for the CheckedChanged event. Using the CheckedChanged event we can know the CheckBox's current state and can perform any task when the page post to the server.




The following example demonstrates to us how to use CheckBox control in asp.net. Here we create a web form with a Label and two CheckBox control. When someone checks the first CheckBox then the label shows a message that he checked first CheckBox. The second CheckBox programmatically checked when user checked the first CheckBox.




CheckBoxExample.aspx



<%@ Page Language="C#" %>

<!DOCTYPE html>

<script runat="server">
    protected void CheckBox1_CheckChanged(object sender, System.EventArgs e) {

        if (CheckBox1.Checked == true) {
            Label1.Text = "WOW! You are a member of an asp.net user group.";
            Label1.ForeColor = System.Drawing.Color.Green;
        }
        else{
            Label1.Text = "You are not a member of any asp.net user group.";
            Label1.ForeColor = System.Drawing.Color.Crimson;
        }
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title>How to use CheckBox control in asp.net</title>
    </head>
   
<body style="padding:25px">
    <form id="form1" runat="server">
    <div>
        <h2 style="color:MidnightBlue; font-style:italic;">      
            How to use CheckBox control
        </h2>      
        <hr width="450" align="left" color="Gainsboro" />
        <asp:Label
            ID="Label1"
            runat="server"
            Font-Bold="true"
            Font-Names="Comic Sans MS"
            ForeColor="Crimson"
            Font-Italic="true"
            Font-Size="X-Large"
            Width="350"
            />
        <br /><br />
        <asp:CheckBox 
            ID="CheckBox1" 
            runat="server" 
            Text="Are you an asp.net user group member?" 
            OnCheckedChanged="CheckBox1_CheckChanged" 
            AutoPostBack="true"
            Font-Names="Serif"
            Font-Size="X-Large"
            />
    </div>
    </form>
</body>
</html>












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