Asp.net gridview check all and uncheck all in a single Header Template checkbox

In this article I will explain how to check all and unchecked all in a single Header Template checkbox in GridView in ASP.NET.

First we need to add a check Box in GridView Header Template. Below is the design code for Check Box.

<asp:GridView ID="gvNew" runat="server" AutoGenerateColumns="false">

<Columns>
 <asp:TemplateField HeaderText="Monthly Report" HeaderStyle-Height="30px" FooterStyle-Height="25px">

<HeaderTemplate>

<asp:CheckBox ID="RbtIncludeMonthlyReportHT" runat="server" AutoPostBack="true" Text="Monthly Report"                                             OnCheckedChanged="RbtIncludeMonthlyReportHT_CheckedChanged" />

</ContentTemplate> 

</HeaderTemplate>

 <ItemTemplate>

<asp:UpdatePanel ID="upTest" runat="server">

<ContentTemplate>

<asp:CheckBox ID="RbtIncludeMonthlyReport" runat="server" AutoPostBack="true"   Checked='<%# Convert.ToBoolean(Eval("MonthlyReportFlag")) %>' />

 </ContentTemplate>

</asp:UpdatePanel>

</ItemTemplate>                                                      

</asp:TemplateField>

</Columns>

</asp:GridView>

RowDataBound event for binding data to check box

protected void gvNew_RowDataBound(object sender, GridViewRowEventArgs e)

    {

if (e.Row.RowType == DataControlRowType.Header)

        {

            CheckBox checkboxall = e.Row.FindControl("RbtIncludeMonthlyReportHT") as CheckBox;           

            if (checkboxall != null)

            {

                if (ViewState["MonthlyReport"] != null)

                {

                    checkboxall.Checked = (bool)ViewState["MonthlyReport"];

                    ViewState["MonthlyReport"] = null;

                }

            }

        }

}

Below is the code for saving check box information to DataBase.

protected void RbtIncludeMonthlyReportHT_CheckedChanged(object sender, EventArgs e)

    {

        className objClass=new className();

        CheckBox chk1 = default(CheckBox);

        chk1 = (CheckBox)gvNew.HeaderRow.Cells[0].FindControl("RbtIncludeMonthlyReportHT");

        bool MonthlyReport = chk1.Checked;

        ViewState["MonthlyReport"] = MonthlyReport;

        if (MonthlyReport == true)

        {          

           objClass. Month = 1;

           // Update information in DB

           objClass.GetMonthlyFlag();

        }

        else

        {           

            objClass. Month = 0;

           // Update information in DB

            objClass.GetMonthlyFlag();

        }

            if (MonthlyReport == true)

            {

                CheckBox chkMonth = (CheckBox)gvNew.HeaderRow.Cells[0].FindControl("RbtIncludeMonthlyReportHT");

            }

            else

            {

                CheckBox chkMonth = (CheckBox)gvNew.HeaderRow.Cells[0].FindControl("RbtIncludeMonthlyReportHT");

            }

        }

    }