DataGridView ContextMenuStrip issue

[ddanbe]

Hi,
You can simulate this by starting a new WinForm app.
Add a datagridview and add some columns.
Add a contextmenustrip, add a menuitem, doubleclick it to get a clickhandler.
Attach the menustrip to the datagridview in the properties window of the DGV.
Then refer to this code and the comments.

private void dataGridView1_CellMouseClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right)
            {
                // here we do not come although the contextmenustrip shows up under the mouse pointer
                this.dataGridView1.CurrentCell = this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex];

                this.contextMenuStrip1.Show(this.dataGridView1, new Point(e.RowIndex, e.ColumnIndex));
            }
        }

        private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
        {
            
            if (e.Button == MouseButtons.Right)
            {
                // here we do come but with the added effect that the contextmenu shows up in he upper right
                // corner of the DGV before appearing under the mouse pointer as it should.
                this.dataGridView1.CurrentCell = this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex];

                this.contextMenuStrip1.Show(this.dataGridView1, new Point(e.RowIndex, e.ColumnIndex));
            }
        }

        private void removeColumnToolStripMenuItem_Click(object sender, EventArgs e)
        {
            // columnindex not always correct
            this.dataGridView1.Columns.RemoveAt(this.dataGridView1.CurrentCell.ColumnIndex);
        }

So with the mousedown I get the correct results with an extra menustrip popping up, with the mouseclick I get the correct menustrip but sometimes the wrong column gets deleted.
Can anyone explain what is happening, tried many things but I'm getting out of resources.
Any answer would be very much appreciated!

[kvprajapati]

Hi!

Do not use Show method of contextMenuStrip and no need to handle cell mouse events. In fact, Show() method parameters - ColumnIndex and RowIndex represent column and row index values not the region of datagridview location.

Here is code (from your snippet :) ).

private void Form1_Load(object sender, EventArgs e)
        {
            dataGridView1.ColumnCount = 4;
            dataGridView1.Columns[0].Name = "No1";
            dataGridView1.Columns[1].Name = "No2";
            dataGridView1.Columns[2].Name = "No3";
            dataGridView1.Columns[3].Name = "No4";

            dataGridView1.SelectionMode = DataGridViewSelectionMode.CellSelect;
            dataGridView1.CellMouseEnter += (sa, ea) =>
                {
                    if (ea.ColumnIndex != -1 && ea.RowIndex != -1)
                        dataGridView1.CurrentCell = dataGridView1.Rows[ea.RowIndex].Cells[ea.ColumnIndex];

                };
            testToolStripMenuItem.Click += (sa, ea) =>
                {
                    if (this.dataGridView1.CurrentCell != null)
                        this.dataGridView1.Columns.RemoveAt(this.dataGridView1.CurrentCell.ColumnIndex);

                    if (this.dataGridView1.CurrentCell == null)
                        dataGridView1.ContextMenuStrip = null;
                };
        }

Please let me know if you have any questions.

[ddanbe]

Adatapost, amazing :-O
Thank you, thank you.
This shows off some deep knowledge.
I definitely have to work myself into LINQ I guess.:-/
One question: what does sa in your code mean?

[kvprajapati]

Thanks danny!

>One question: what does sa in your code mean?

sa - sender argument. (first argument of event handler - object sender)

I've used lambda expression to handle events. Lambda expressions and Anonymous functions in C# are amazing! Please refer following links for further details :

1. Anonymous Functions (C# Programming Guide)
2. Lambda Expressions (C# Programming Guide)

[ddanbe]

Yes of course!
Thanks for the clarification and the links :)

[watsonsimler]

Datagridview right click and delete row...

    private void dataGridView1_CellMouseUp(object sender, DataGridViewCellMouseEventArgs e)
    {
        if (e.Button == MouseButtons.Right) 
        {
            this.dataGridView1.Rows[e.RowIndex].Selected = true; 
            this.rowIndex = e.RowIndex;
            this.dataGridView1.CurrentCell = this.dataGridView1.Rows[e.RowIndex].Cells[1];
            this.contextMenuStrip1.Show(this.dataGridView1, e.Location);
            contextMenuStrip1.Show(Cursor.Position);
        }
    }

Source...Right click and delete from datagridview

watson

[kira1220]

how to code datagridview with a msaccess database that you can add data in datagrid...update and delete data??

[ddanbe]

Begin by starting a new thread!