Sum of cell based on CheckBox in GridView using C# in ASP.Net

Hi moayyad,

I have created sample that fullfill your requirement.

HTML

<div>
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
        <Columns>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:CheckBox ID="cbSalary" runat="server" AutoPostBack="true" OnCheckedChanged="CheckedChanged" />
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField="Salary" HeaderText="Salary" />
        </Columns>
    </asp:GridView>
</div>
<br />
<asp:Label ID="lblSum" runat="server" />

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[1] { new DataColumn("Salary", typeof(decimal)) });
        dt.Rows.Add(1000);
        dt.Rows.Add(2000);
        dt.Rows.Add(3000);
        dt.Rows.Add(4000);
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}

protected void CheckedChanged(object sender, EventArgs e)
{
    decimal total = 0;
    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox cb = row.FindControl("cbSalary") as CheckBox;
        decimal salary = Convert.ToDecimal(row.Cells[1].Text);

        if (cb.Checked)
        {
            total = total + salary;
        }
    }

    lblSum.Text = total.ToString();
}

Screenshot