GridView Hide Column by code

GridView.Columns.Count will always be 0 when your GridView has its AutoGenerateColumns property set to true (default is true).

You can explicitly declare your columns and set the AutoGenerateColumns property to false, or you can use this in your codebehind:

GridView.Rows[0].Cells.Count

to get the column count once your GridView data has been bound, or this:

protected void GridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
    e.Row.Cells[index].Visible = false;
}

to set a column invisible using your GridView’s RowDataBound event.