How to paste only valid value in textbox.

[S a n d y]

No, I do not understand how to do it?

[N a v a n e e t h]

Check this[^]

Navaneeth How to use google | Ask smart questions

[Vikram A Punathambekar]

Handle the TextChanged event. Even better, use a NumericUpDown control.

Cheers, Vıkram.

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"You idiot British surprise me that your generators which grew up after Mid 50s had no brain at all." - Adnan Siddiqi.

[DaveyM69]

override WndProc, trap WM_PASTE and process there. Check out pinvoke.net.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

[S a n d y]

Thanks, but I don't know how to use this. Please give me a little example.

[Vengatachalapathy Palanivel]

If that's a web application or windows application . If it's a web application, then you can go about by Javascripts.

[DaveyM69]

OK. This example creates a customized TextBox so add this class, build then drop onto a form.

public class RestrictedTextBox : TextBox
{
    private const int WM\_PASTE = 0x0302;

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM\_PASTE)
        {
            if (!IsPasteValid())
            {
                m.Result = IntPtr.Zero;
                return;
            }
        }
        base.WndProc(ref m);
    }

    private bool IsPasteValid()
    {
        bool rtn = false;
        IDataObject obj = Clipboard.GetDataObject();
        string pasteString = (string)obj.GetData(typeof(string));
        // Do checks on pasteString here and set rtn to true if OK.
        return rtn;
    }
}

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

[S a n d y]

Its Window application.

[S a n d y]

Thanks

[Vengatachalapathy Palanivel]

I think, this piece of code will help you out...

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if ( Convert.ToInt16(e.KeyChar) >= 48 && Convert.ToInt16(e.KeyChar) <=57)
{
e.KeyChar = e.KeyChar;
}
else
{
e.KeyChar = Convert.ToChar(0);
}
}

    private void textBox1\_TextChanged(object sender, EventArgs e)
    {
        char\[\] strSample = new char\[((System.Windows.Forms.TextBox)(sender)).Text.ToString().Length\];

        strSample = (((System.Windows.Forms.TextBox)(sender)).Text).ToCharArray();

        for (int i=0; i<strSample.Length;i++)
        {
            if (Convert.ToInt16(strSample\[i\]) >= 48 && Convert.ToInt16(strSample\[i\]) <= 57)
            {
                continue;
            }
            else
            {
                ((System.Windows.Forms.TextBox)(sender)).Text = "";
                break;
            }
        }
        
    }

Try this and let me know if you have any concerns. Regards, Vengat P

[S a n d y]

Thanks Vengat, Everything is worked fine but if we paste characters then textbox goes blank. In that case we want current value of textbox. Then how to do that.

[Vengatachalapathy Palanivel]

I am also new to windows application, but i'm sure that, you can bind the value of textbox again with the help of a global variable(that will be updated for each key press event and text change event). Sample: private string strTestVal = string.Empty; on keypress event: in if condition strTestVal = textBox1.Text.ToString(); on text change event: textBox1.Text = strTestVal;

Regards, Vengat P