TextBox. How to Validate for Number??

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I have two TextBoxes. I have a button that calls a method that will use the input from the text boxes ONLY if a number is entered. How do I do I do this? Tried for several nights-- but I keep crashing on non-numerical input... --thanks in advance

[Dan Neely]

Void OnButtonClick(...) { Try { int i = Convert.ToInt(textbox.Text); } catch { return } DoSomething(); }

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Dan- thanks. I have already tried the code you've shown. My problem is that BOTH text boxes are "tied" to the button event-- so I keep getting an infnite loop of two MessageBoxes (each from the catch statements of the two TextBoxes) when there is an invalid entry....

[Dan Neely]

I'm not sure I follow you here. Are you doing your check event when the button is clicked, or when a user modifies the content of eitehr box?

[Anonymous]

Ok Here's what I did...program crashes on invalid input and I get endless Message boxes that won't close on 'OK'. Thanks... This is driving me nuts....:confused: /////////////////////////////// void DrawComplexNumber1(Graphics g) { Pen p = c_xy.GetNextPen(); p.DashStyle = DashStyle.Dot; c_xy.SetOrigin(xIndent + graphRect.Width/2, yIndent + graphRect.Y/2); try { cmplxValue1.Real = Convert.ToDouble(textComplex_1Real.Text); } catch { MessageBox.Show("Error!"); } try { cmplxValue1.Imaginary = Convert.ToDouble(textComplex_1Imaginary.Text); } catch { MessageBox.Show("Error!"); } g.DrawLine(p, 250, 250, (float)(250 + (xIndent * cmplxValue1.Real)), (float)(250 - (yIndent * cmplxValue1.Imaginary))); ////////////////////////////////////////////// private void complex_1OK_Click_1(object sender, System.EventArgs e) { drawLine1 = !drawLine1; Invalidate(); } /////////////////////////////////////////Paint Handler .... if(drawLine1) DrawComplexNumber1(e.Graphics); }

[Anonymous]

hi How about using int32.parse(textbox.text) ? Banshi Khinchi

[nps_ltv]

You see the following code : private void button1_Click(object sender, System.EventArgs e) { int number = 0; try { number = System.Convert.ToInt32(textBox1.Text); } catch(Exception ex) { System.Windows.Forms.MessageBox.Show("Input is not a number !"); textBox1.Focus(); return; } DoSomething(number); } private void DoSomething(int iNumber) { // Your code is here ... } with textBox1, textBox2 are two instances of TextBox class and button1 is a instance of Button class. NPS.

[Luis Alonso Ramos]

Handle the Validating event for both text boxes:

private void TextBox_Validating(object sender, CancelEventArgs e)
{
    TextBox textBox = sender as TextBox;
    if(textBox == null)  // Ensure this is indeed a TextBox
        return;
 
    // Allow the user to leave the text box without typing anything
    if(textBox.TextLength == 0)
        return;
 
    bool error = false;
 
    try
    {
        int n = Convert.ToInt32(textBox);
        if(n < 0 || n > 100)  // Check range if necessary
            error = true;
    }
    catch(FormatException)
    {
        // Could not parse the number
        error = true;
    }
    finally
    {
        if(error)
        {
            MessageBox.Show("Please enter a valid number");
 
            textBox.SelectAll();
            textBox.Focus();
 
            e.Cancel = true;  // Don't allow focus to leave the control
        }
    }
}

When the user tries to take focus away from the control, its contents will be validated. If invalid, the user won't be allowed to leave the control unless he corrects it or leaves it empty. Then in you button handler, just validate that the text boxes have anything. If they do, it's surely a valid number. I hope this helps! -- LuisR

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Luis Alonso Ramos Intelectix - Chihuahua, Mexico Not much here: My CP Blog!

The amount of sleep the average person needs is five more minutes. -- Vikram A Punathambekar, Aug. 11, 2005

[albCode]

In keypress of textbox-es write this code: e.Handled = e.KeyChar < '0' || e.KeyChar > '9'; u are able to write only numers no other charachters I hope this helps u