Row Hiding <%# Container.DataItemIndex+1 %> is not correct

Hi lejo,
To hide rows in an ASP.NET GridView, you can use the Visible property of the GridViewRow object. You can access the row object using the Row property of the GridViewRowEventArgs object in the RowDataBound event of the GridView.

Based on your problem statement you can use the below code to hide rows 2 and 5 in a GridView:

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        // Hide rows 2 and 5
        if (e.Row.RowIndex == 1 || e.Row.RowIndex == 4)
        {
            e.Row.Visible = false;
        }
    }
}

Keep in mind that the RowIndex property of the GridViewRow object is zero-based, so the first row has an index of 0, the second row has an index of 1, and so on.

if you want fix the row numbers after hiding some rows, you can use the RowDataBound event to update the row numbers in the template field. Use the below code snippet to do this:

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        // Update the row numbers after hiding some rows
        int rowNumber = e.Row.RowIndex + 1;
        if (e.Row.RowIndex > 1)
        {
            rowNumber -= 2;
        }
        if (e.Row.RowIndex > 4)
        {
            rowNumber--;
        }

        Label lblRowNumber = (Label)e.Row.FindControl("lblRowNumber");
        lblRowNumber.Text = rowNumber.ToString();
    }
}

we are using a Label control with an ID of "lblRowNumber" in the template field to display the row number. You can adjust the code to fit your specific requirements.