CODEWITHSUNDEEP
c#windowswinformstextboxc#-2.0
GiriYahoo
GiriYahoo

Reputation:

Validating WinForms TextBox (in C#)

In TextBox_Leave event i need to check whether numbers entered in textbox is in serial number or not.If it is not in order then i need to display a message as "number" is missing

For example :

In textbox i have entered 3 and click tab : I need to display message as "Number is not in order , number "1" and "2" is missing "

Upvotes: 0

Views: 11872

Answers (5)

user3740175
user3740175

Reputation: 1

I will show you how to validate Validating WinForms TextBox (in C#).

  1. Create a function:

    public static void ChkBlankTextBoxes(object sender, string type)
{

    if (sender is TextBox)
    {
        TextBox textbox = sender as TextBox;
        if (string.IsNullOrEmpty(textbox.Text))
        {
            MessageBox.Show("Please enter correct value value..");
            textbox.Focus();

        }
    }
}

  2. Call to created function:

    ChkBlankTextBoxes(txt_userID, textBoxtype);

ChkBlankTextBoxes(txt_password, textBoxtype);

Upvotes: 0

Karthik
Karthik

Reputation: 187

Alternatively you can also use Validating event of the text box.

  private void textBox1_Validating( object sender, CancelEventArgs e )
  {
      if ( textBox1.Text == "3" )
          e.Cancel = true;
  }

The text-box wont loose focus until it receives a valid input.

Upvotes: 1

THE DOCTOR
THE DOCTOR

Reputation: 4555

Try using a Masked TextBox control and set a custom property for this type of field validation.

Upvotes: 1

tzup
tzup

Reputation: 3604

One trick is to retain focus in the textbox when trying to leave (with TAB for instance) in case of some condition (missing number): 

 private void textBox1_Leave(object sender, EventArgs e)
    {
        TextBox tb = (TextBox)sender;

        if (tb.Text == "3")
            tb.Focus();
    }

Assuming you are using a standard textbox. You could also use third party controls that where you can cancel an event (e.Cancel = true) on some condition.

Upvotes: 1

Lennaert
Lennaert

Reputation: 2465

I don't know whether this also works in c#2.0, this is my experience in c#3.0:

Why do you use TextBox_Leave for that? The Validating-event should be used for validating whether input is correct.

Combine using the Validating-event with using an ErrorProvider (you can just drag it from the toolbox onto the form) to set an error message: it will be displayed as a (blinking) exclamation mark in a red triangle.

An ErrorProvider can also block any submit-actions.

Upvotes: 7

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