In this article I will explain with an example, how to select (check) one (single) CheckBox in ASP.Net GridView using JavaScript.
By default, multiple CheckBoxes in GridView are meant for multiple selection, thus in order to make it work as single selection i.e. only one (single) CheckBox can be selected at a time, JavaScript needs to be used to achieve the same.
 
 

HTML Markup

The HTML Markup consists of:
GridView - For displaying data.

Columns

The GridView consists of one TemplateField column and Three BoundField columns.
TemplateField - The TemplateField column consists of ItemTemplate.
ItemTemplate – It consists of a CheckBox.
<asp:GridView ID="gvCustomers" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:CheckBox ID="chkRow" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Id" HeaderText="Customer Id" HeaderStyle-Width="80" />
        <asp:BoundField DataField="Name" HeaderText="Name" HeaderStyle-Width="120" />
        <asp:BoundField DataField="Country" HeaderText="Country" HeaderStyle-Width="120" />
    </Columns>
</asp:GridView>
 
 

Namespaces

You will need to import the following namespace.
C#
using System.Data;
 
VB.Net
Imports System.Data
 
 

Binding the ASP.Net GridView control

Inside the Page_Load event handler, an object of DataTable is created.
Then, three columns are added to the DataTable Columns collection using the AddRange method.
Once the schema is ready i.e. all the columns are defined, some rows have been added using the Rows.Add method.
Finally, the DataTable is assigned to the DataSource property of the GridView and the GridView is populated.
Note: You can learn more about this dynamic DataTable in my article Create DataTable dynamically and bind to GridView in ASP.Net.
 
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[3] {
                            new DataColumn("Id"),
                            new DataColumn("Name"),
                            new DataColumn("Country") });
        dt.Rows.Add(1, "John Hammond", "United States");
        dt.Rows.Add(2, "Mudassar Khan", "India");
        dt.Rows.Add(3, "Suzanne Mathews", "France");
        dt.Rows.Add(4, "Robert Schidner", "Russia");
        gvCustomers.DataSource = dt;
        gvCustomers.DataBind();
    }
}
 
VB.Net
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.AddRange(New DataColumn(2) {
                            New DataColumn("Id"),
                            New DataColumn("Name"),
                            New DataColumn("Country")})
        dt.Rows.Add(1, "John Hammond", "United States")
        dt.Rows.Add(2, "Mudassar Khan", "India")
        dt.Rows.Add(3, "Suzanne Mathews", "France")
        dt.Rows.Add(4, "Robert Schidner", "Russia")
        gvCustomers.DataSource = dt
        gvCustomers.DataBind()
    End If
End Sub
 
 

JavaScript function to select one (single) CheckBox from multiple CheckBoxes in GridView

Inside the JavaScript window onload event handler, first the GridView is referenced and then all the CheckBoxes inside it are referenced.
Then a loop is executed over the CheckBoxes and Click event handler is attached.
Inside the Click event handler, a check is made to make sure whether the clicked CheckBox is checked and if it is checked then all the other CheckBoxes are unchecked.
<script type="text/javascript">
    window.onload = function () {
        var grid = document.getElementById("<%= gvCustomers.ClientID%>");
        var chks = grid.getElementsByTagName("INPUT");
        for (var i = 0; i < chks.length; i++) {
            if (chks[i].type == "checkbox") {
                chks[i].onclick = function () {
                    for (var i = 0; i < chks.length; i++) {
                        if (chks[i] != this && this.checked) {
                            chks[i].checked = false;
                        }
                    }
                };
            }
        }
    };
</script>
 
 

Screenshot

Select (Check) one (single) CheckBox in ASP.Net GridView using JavaScript
 
 

Browser Compatibility

The above code has been tested in the following browsers.
Microsoft Edge   FireFox  Chrome  Safari  Opera
* All browser logos displayed above are property of their respective owners.
 
 

Demo

View Demo
 
 

Downloads

Download Code