Selection of text inside cells of datagridview

Question

Selection of text inside cells of datagridview

rahul kumar 605

Hi ,

how can we disable the text selection by the user when the cell is in edit mode inside a datagridview . I searched for the whole dastagridview but doesn't found anything .

Anonymous

2023-11-07T10:41:01.1233333+00:00

Hi @rahul kumar , Welcome to Microsoft Q&A,

I don't understand what you want to do. Since we are in edit mode, what does disable the text selection mean?

rahul kumar 605

@Anonymous , for this Please consider two scenarios

the cell is in edit mode , user types vijay and then using shift and left arrow key , selects the text . this thing i want to disable .
the datagridview loads with some data , cell[0,0] has written Vijay inside it . user double clicks inside the cell , user tries to select the whole text by using above or using double click on mouse .

i am using the below event which gives me the instance of textbox in edit mode . Would that makes the solution easier for me

    protected override void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e)
        {
            e.Control.KeyPress -= new KeyPressEventHandler(textbox_keypress);
            e.Control.TextChanged -= new EventHandler(TextBox_TextChanged);
            e.Control.KeyDown -= new KeyEventHandler(TextBox_KeyDown);
            e.Control.Enter -= new EventHandler(TextBox_Enter);
            if (this.CurrentCell.ColumnIndex == 0) // Assuming the first column has an index of 0
            {
                TextBox textBox = e.Control as TextBox;
                if (textBox != null)
                {
                   
                    textBox.TextChanged += TextBox_TextChanged; 
                    textBox.KeyDown += TextBox_KeyDown; 
                    textBox.Enter += TextBox_Enter;
                }
            }
            base.OnEditingControlShowing(e);
        }

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Anonymous

2023-11-07T10:41:01.1233333+00:00

Hi @rahul kumar , Welcome to Microsoft Q&A,

I don't understand what you want to do. Since we are in edit mode, what does disable the text selection mean?
rahul kumar 605 Reputation points

2023-11-07T10:47:13.91+00:00

@Anonymous , for this Please consider two scenarios

the cell is in edit mode , user types vijay and then using shift and left arrow key , selects the text . this thing i want to disable .

the datagridview loads with some data , cell[0,0] has written Vijay inside it . user double clicks inside the cell , user tries to select the whole text by using above or using double click on mouse .

i am using the below event which gives me the instance of textbox in edit mode . Would that makes the solution easier for me

protected override void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e) { e.Control.KeyPress -= new KeyPressEventHandler(textbox_keypress); e.Control.TextChanged -= new EventHandler(TextBox_TextChanged); e.Control.KeyDown -= new KeyEventHandler(TextBox_KeyDown); e.Control.Enter -= new EventHandler(TextBox_Enter); if (this.CurrentCell.ColumnIndex == 0) // Assuming the first column has an index of 0 { TextBox textBox = e.Control as TextBox; if (textBox != null) { textBox.TextChanged += TextBox_TextChanged; textBox.KeyDown += TextBox_KeyDown; textBox.Enter += TextBox_Enter; } } base.OnEditingControlShowing(e); }

Answer 1

KOZ6.0 6,655

Create a class that inherits from the NativeWindow class and disallows selection behavior.

using System.Windows.Forms;

class DisableSelectWindow : NativeWindow
{
    private bool MouseIsDown = false;

    public DisableSelectWindow(TextBox owner) {
        AssignHandle(owner.Handle);
    }

    const int
        WM_KEYDOWN = 0x0100,
        WM_CHAR = 0x0102,
        WM_IME_CHAR = 0x0286,
        WM_SYSCHAR = 0x0106,
        WM_MOUSEMOVE = 0x0200,
        WM_LBUTTONDOWN = 0x0201,
        WM_LBUTTONDBLCLK = 0x0203,
        WM_LBUTTONUP = 0x0202,
        WM_CAPTURECHANGED = 0x0215,
        EM_SETSEL = 0x00B1;

    const char CTRL_A = '\x01';

    protected override void WndProc(ref Message m) {
        switch (m.Msg) {
            case WM_KEYDOWN:
                Keys keyCode = (Keys)(int)(m.WParam.ToInt64() & 0xffff);
                if (Control.ModifierKeys.HasFlag(Keys.Shift)) {
                    switch (keyCode) {
                        case Keys.Up:
                        case Keys.Down:
                        case Keys.Right:
                        case Keys.Left:
                            return;
                    }
                }
                base.WndProc(ref m);
                break;
            case WM_CHAR:
            case WM_IME_CHAR:
            case WM_SYSCHAR:
                char c = (char)(m.WParam.ToInt64() & 0xffff);
                if (c == CTRL_A) {
                    return;
                }
                base.WndProc(ref m);
                break;
            case WM_CAPTURECHANGED:
                MouseIsDown = false;
                base.WndProc(ref m);
                break;
            case WM_LBUTTONDOWN:
                MouseIsDown = true;
                base.WndProc(ref m);
                break;
            case WM_LBUTTONUP:
                MouseIsDown = false;
                base.WndProc(ref m);
                break;
            case WM_LBUTTONDBLCLK:
                break;
            case WM_MOUSEMOVE:
                if (!MouseIsDown) {
                    base.WndProc(ref m);
                }
                break;
            case EM_SETSEL:
                break;
            default:
                base.WndProc(ref m);
                break;
        }
    }
}

Use this like this:

DisableSelectWindow disableSelectWindow;

protected override void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e) {
    TextBox textBox = e.Control as TextBox;
    if (textBox != null) {
        disableSelectWindow = new DisableSelectWindow(textBox);
    }
    base.OnEditingControlShowing(e);
}

protected override void OnCellEndEdit(DataGridViewCellEventArgs e) {
    if (disableSelectWindow != null) {
        disableSelectWindow.ReleaseHandle();
        disableSelectWindow = null;
    }
    base.OnCellEndEdit(e);
}

It feels strange, what is the purpose?

rahul kumar 605 Reputation points

2023-11-08T03:48:54.1866667+00:00

@KOZ6.0 , unfortunately it is not working .

KOZ6.0 6,655

How do you use this? Can't it work with just this code?

public class CustomDataGridView : DataGridView
{
    DisableSelectWindow disableSelectWindow;

    protected override void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e) {
        TextBox textBox = e.Control as TextBox;
        if (textBox != null) {
            disableSelectWindow = new DisableSelectWindow(textBox);
        }
        base.OnEditingControlShowing(e);
    }

    protected override void OnCellEndEdit(DataGridViewCellEventArgs e) {
        if (disableSelectWindow != null) {
            disableSelectWindow.ReleaseHandle();
            disableSelectWindow = null;
        }
        base.OnCellEndEdit(e);
    }
}

rahul kumar 605 Reputation points

2023-11-08T10:02:39.7666667+00:00

@KOZ6.0 pls see my project at https://github.com/RahulKumarcool/Rahulkumar
it is not working

sometimes working for column1 but not for rest of columns .
KOZ6.0 6,655 Reputation points

2023-11-08T11:03:35.4933333+00:00

Changing the RightToLeft property destroys the window and creates a new one. That's where NativeWindow stops working.

Create an instance of DisableSelectWindow after changing the RightToLeft property.
rahul kumar 605 Reputation points

2023-11-08T11:10:11.2766667+00:00

@KOZ6.0 , doesn't help much . sometimes its working , sometimes not . may be there is a issue with the event sequence in my code .

KOZ6.0 6,655

Please fix the code

protected override void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e)
{
    TextBox textBox = e.Control as TextBox; // var tbox = (TextBox)e.Control;
    if (textBox != null)
    {
        if (this.CurrentCell.ColumnIndex > 0 && this.CurrentCell.RowIndex >= 0) {
            textBox.RightToLeft = RightToLeft.Yes;
            textBox.TextAlign = HorizontalAlignment.Right;
        }
        disableSelectWindow = new DisableSelectWindow(textBox);
        textBox.ContextMenuStrip = new ContextMenuStrip(); // disable contect menu 
    }
    base.OnEditingControlShowing(e);
}

rahul kumar 605 Reputation points

2023-11-08T11:23:45.7+00:00

@KOZ6.0 , same result for column3 ( columnindex 2)

KOZ6.0 6,655

If enter column3, the window will be recreated. Modify the DisableSelectWindow class.

using System;
using System.Windows.Forms;

class DisableSelectWindow : NativeWindow, IDisposable
{
    private bool MouseIsDown = false;
    private TextBox Owner;
    private bool disposedValue;

    public DisableSelectWindow(TextBox owner) {
        Owner = owner;
        if (Owner.IsHandleCreated) {
            AssignHandle(Owner.Handle);
        }
        Owner.HandleCreated += Owner_HandleCreated;
    }

    private void Owner_HandleCreated(object sender, EventArgs e) {
        TextBox owner = (TextBox)sender;
        AssignHandle(owner.Handle);
        MouseIsDown = false;
    }

    protected virtual void Dispose(bool disposing) {
        if (!disposedValue) {
            disposedValue = true;
            ReleaseHandle();
            Owner.HandleCreated -= Owner_HandleCreated;
            Owner = null;
        }
    }

    ~DisableSelectWindow() {
        Dispose(false);
    }

    public void Dispose() {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    const int
        WM_NCDESTROY = 0x0082,
        WM_KEYDOWN = 0x0100,
        WM_CHAR = 0x0102,
        WM_IME_CHAR = 0x0286,
        WM_SYSCHAR = 0x0106,
        WM_MOUSEMOVE = 0x0200,
        WM_LBUTTONDOWN = 0x0201,
        WM_LBUTTONDBLCLK = 0x0203,
        WM_LBUTTONUP = 0x0202,
        WM_CAPTURECHANGED = 0x0215,
        EM_SETSEL = 0x00B1;

    const char CTRL_A = '\x01';

    protected override void WndProc(ref Message m) {
        switch (m.Msg) {
            case WM_NCDESTROY:
                base.WndProc(ref m);
                ReleaseHandle();
                break;

            case WM_KEYDOWN:
                Keys keyCode = (Keys)(int)(m.WParam.ToInt64() & 0xffff);
                if (Control.ModifierKeys.HasFlag(Keys.Shift)) {
                    switch (keyCode) {
                        case Keys.Up:
                        case Keys.Down:
                        case Keys.Right:
                        case Keys.Left:
                            return;
                    }
                }
                base.WndProc(ref m);
                break;
            case WM_CHAR:
            case WM_IME_CHAR:
            case WM_SYSCHAR:
                char c = (char)(m.WParam.ToInt64() & 0xffff);
                if (c == CTRL_A) {
                    return;
                }
                base.WndProc(ref m);
                break;
            case WM_CAPTURECHANGED:
                MouseIsDown = false;
                base.WndProc(ref m);
                break;
            case WM_LBUTTONDOWN:
                MouseIsDown = true;
                base.WndProc(ref m);
                break;
            case WM_LBUTTONUP:
                MouseIsDown = false;
                base.WndProc(ref m);
                break;
            case WM_LBUTTONDBLCLK:
                break;
            case WM_MOUSEMOVE:
                if (!MouseIsDown) {
                    base.WndProc(ref m);
                }
                break;
            case EM_SETSEL:
                break;
            default:
                base.WndProc(ref m);
                break;
        }
    }
}

Please modify OnCellEndEdit.

protected override void OnCellEndEdit(DataGridViewCellEventArgs e) {
    if (disableSelectWindow != null) {
        // disableSelectWindow.ReleaseHandle(); // ■ delete
        disableSelectWindow.Dispose();          // ■ add
        disableSelectWindow = null;
    }
    base.OnCellEndEdit(e);
}

rahul kumar 605 Reputation points

2023-11-08T12:16:47.3833333+00:00

Thanks @KOZ6.0 , now its working perfect

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Selection of text inside cells of datagridview

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