Text Box Validation

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hello Every ,

Here Is my Question ... My project have 15 Form At Many Forms I need to validate (like alphabets only and number only )i want to write a common code for all the same text box ...is there any way to impalement such code ...please help me ..i m bit new in C#.net

any help will be appreciated

thanks in Ad advanced

lakhanp22

Posted 12-Jun-12 6:19am

Lakhan Aanjana

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Maciej Los 12-Jun-12 13:19pm

What kind of validation do you need? Please, be more specific. Provide more details.

RDBurmon 13-Jun-12 9:31am

Thanks Everyone who replied to this thread , So LakhanP, I think you have got enough responses and you should be able to mark it as your answer and close the thread. Please do so.

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Emzari · Answer 1 · 2012-06-12T07:32:00

This is an implementation of an numeric text box you can use it as is or customize by your needs.

C#

[ToolboxBitmap(typeof(System.Windows.Forms.TextBox))]
public class FilteredTextBox : TextBox
{
    private TextBoxInputFilter tbif = TextBoxInputFilter.Standard;
    private bool nonNumberEntered = false;

    public enum TextBoxInputFilter  //input filter enumeration
    {
        Standard = 1,
        Numeric = 2,
    }

    public TextBoxInputFilter InputFilter //this property holds input filter state
    {
        get { return tbif; }
        set { tbif = value; }
    }
    protected override void OnKeyDown(KeyEventArgs e)
    {
        if (this.InputFilter == TextBoxInputFilter.Numeric)
        {
            nonNumberEntered = false;
            //Check if pressed key is a number from a top line of keyboard
            if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
            {
                //Check if pressed key is a number from a numeric keyboard
                if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
                {
                    //determine if it is a BACSPACE key
                    if (e.KeyCode != Keys.Back)
                    {
                        nonNumberEntered = true;
                    }
                }
            }
        }
        base.OnKeyDown(e);
    }
    protected override void OnKeyPress(KeyPressEventArgs e)
    {
        if (this.InputFilter == TextBoxInputFilter.Numeric)
        {
            if (nonNumberEntered == true)
            {
                //prevent entering a symbol because it is not a number
                SystemSounds.Beep.Play();
                e.Handled = true;
            }
        }
        base.OnKeyPress(e);
    }
}

David_Accu · Answer 2 · 2012-06-12T07:29:00

Hi!

You can create a custom control derived from TextBox so that it accepts only validated input.For this you have to use class(.cs file) in C#.Net. Here is sample example of the NumericTextBox class which shows how to impliment and place it on the form.

You can implement your validation in class.

Regards.

Clifford Nelson · Answer 3 · 2012-06-12T07:32:00

You do not give an environment, but I assume it is WinForms. On all events there is a sender. You can determine which control sent the event by using the sender, and you can cast it to the right type (in this case var tb = (TextBox)sender.

You can do the Validating

C#

void TextBox_Validating(object sender, CancelEventArgs e) {
  if( TextBox.Text.Length == 0 )
  {
    MessageBox.Show("Please enter a name", "Error");
    e.Cancel = true;
  }
}

All you need to do is target all the text box events to the same handler.

A quick overview is at http://www.sellsbrothers.com/writing/winformsDataValidation.htm[^]

Text Box Validation

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