Selecting DataGridView Rows Programatically

[nikel]

Hi I have some code in my datagridview's CellMouseDown event to select multiple rows.

It takes back my selection, after doing multiple selections over 1 time. How can I fix this? Note: I don't want to use mouseup event because it will make things worse imo.

Here's my code:

private void SelectDgvItems(bool ClearRequest)
{
    // Check if there's a line
    if (programs_dgv.RowCount <= 0)
    {
        return;
    }
 
    // Sort by name
    programs_dgv.Sort(programs_dgv.Columns[2], ListSortDirection.Ascending);
 
    // Select required rows and set scrolling position
    if (SelectedIndexes != null)
    {
        if (ClearRequest == true)
        {
            programs_dgv.ClearSelection();
        }
 
        for (int i = 0; i <= SelectedIndexes.Count() - 1; i++)
        {
            programs_dgv[1, SelectedIndexes[i]].Selected = true;
        }
    }
 
    MessageBox.Show(LastSelectedIndex.ToString());
}
 
private void programs_dgv_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
    programs_dgv.CommitEdit(DataGridViewDataErrorContexts.Commit);
}
 
private void programs_dgv_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
    CurrentRowIndex = e.RowIndex;
 
    Console.WriteLine(LastSelectedIndex.ToString() + "    " + CurrentRowIndex.ToString());
 
    // Check if there's a line
    if (programs_dgv.Rows == null)
    {
        return;
    }
 
    SelectedIndexes.Clear();
    SelectedIndexes = null;
    SelectedIndexes = new List<int>();
 
    // Reset SelectedIndexes
    for (int i = 0; i <= programs_dgv.RowCount - 1; i++)
    {
        if (programs_dgv.Rows[i].Selected == true)
        {
            SelectedIndexes.Add(i);
        }
    }
 
    // When shift+click
    if (e.Button == MouseButtons.Left && (ModifierKeys & Keys.Shift) == Keys.Shift)
    {
        if (CurrentRowIndex >= 0)
        {
            SelectedIndexes.Clear();
            SelectedIndexes = null;
            SelectedIndexes = new List<int>();
 
            // Set SelectedIndexes
            for (int i = LastSelectedIndex; i <= CurrentRowIndex; i++)
            {
                SelectedIndexes.Add(i);
                Console.WriteLine(SelectedIndexes[i].ToString() + Environment.NewLine);
            }
 
            // Select dgv items (ClearRequest = false)
            SelectDgvItems(false);
            return;
        }
 
        SelectDgvItems(false);
        return;
    }
 
 
 
    // When ctrl is not pressed
    if (e.Button == MouseButtons.Left && (ModifierKeys & Keys.None) == Keys.None)
    {
 
        SelectedIndexes.Clear();
        SelectedIndexes = null;
        SelectedIndexes = new List<int>
        {
            CurrentRowIndex
        };
 
        // Set dgv items (ClearRequest = true)
        SelectDgvItems(true);
 
        return;
    }
 
 
 
    // right click
    if (e.Button == MouseButtons.Right)
    {
        // Open context menu
        int currentMouseOverRow = programs_dgv.HitTest(e.X, e.Y).RowIndex;
 
        if (currentMouseOverRow >= 0)
        {
            Cms_DatagridView.Items[0].Text = "düzenle (" + SelectedIndexes.Count().ToString() + ")";
        }
 
        Cms_DatagridView.Show(programs_dgv, programs_dgv.PointToClient(System.Windows.Forms.Control.MousePosition));
 
        // -----------------------------------------------------------------------------
 
        // If current row isn't selected add it to the list
        if (programs_dgv.Rows[CurrentRowIndex].Selected == false)
        {
            SelectedIndexes.Add(CurrentRowIndex);
        }
 
        SelectedIndexes.Clear();
        SelectedIndexes = null;
        SelectedIndexes = new List<int>
            {
                CurrentRowIndex
            };
 
        SelectDgvItems(true);
 
        LastSelectedIndex = CurrentRowIndex;
        return;
    }
 
}