Question

When I am not selecting checkbox in my gridview and press delete button it show error “No Check box has been selected” but when after that when i select checkbox and click on delete button it still showing that error don’t knw why?
i am not using any database i just use datatable and gridview.

Here is my code on delete button

protected void DeleteButton_Click(object sender, EventArgs e)
{

    var dt = (DataTable)ViewState["CurrentData"];

    if (dt == null)
    {
        return;
    }
    List<DataRow> rowsToDelete = new List<DataRow>();
    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox cb = (CheckBox)row.FindControl("CheckBox1");
        if (cb != null && cb.Checked)
        {
            row.Visible = false;

            //remove row by its index as it should GridViewRow index == DataRow index
            //it is not the best way but from your code I dont have information how your GridView looks
            dt.Rows.RemoveAt(row.RowIndex);

            GridView1.DataSource = dt;
            GridView1.DataBind();

            GridView2.DataSource = dt;
            GridView2.DataBind();

            ViewState["CurrentData"] = dt;
        }
        else
        {
            lblError.Visible = true;
        }
        for (int i = 0; i < rowsToDelete.Count; i++)
        {
            dt.Rows.Remove(rowsToDelete[i]);
        }
    }

Answer 1

Please run this code.

 protected void Button2_Click(object sender, EventArgs e)
 {
    var dt = (DataTable)ViewState["CurrentData"];

    if (dt == null)
    {
        return;
    }

    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox cb = (CheckBox)row.FindControl("CheckBox2");
        if (cb != null && cb.Checked)
        {
            Label1.Visible = false;
            dt.Rows.RemoveAt(row.RowIndex);
            GridView1.DataSource = dt;
            GridView1.DataBind();

            GridView2.DataSource = dt;
            GridView2.DataBind();

            ViewState["CurrentData"] = dt;
        }
        else if (cb.Checked == false)
        {
            Label1.Visible = true;
        }
    }

}