CODEWITHSUNDEEP
c#.netwinforms
whoah
whoah

Reputation: 4443

Validation textbox in winforms

How to validate text in textbox control in winforms?
I have a control, where user have to put string, like "13:55". I want to show MessageBox, when this value will be diffrent, than "XX:YY".
How to do it?
In asp.net it was so easy to make, but how to implement it on winforms?

Upvotes: 1

Views: 6228

Answers (4)

Patrick
Patrick

Reputation: 17973

You could also use an ErrorProvider instead of popping up a messagebox. An example is available on msdn for the ErrorProvider class. Basically you subscribe to the Validated event

this.nameTextBox1.Validated += nameTextBox1Validated;

and then check if the value is valid

private void nameTextBox1Validated(object sender, EventArgs e) {
    if(isNameValid()) {
        // clear error
        nameErrorProvider.SetError(nameTextBox1, String.Empty);
    }
    else {
        // set some helpful message
        nameErrorProvider.SetError(nameTextBox1, "Invalid value.");
    }
}

private bool isNameValid() {
    // The logic for determining if a value is correct
    return nameTextBox1.Text == "hello";
}

the error provider can be created like this

ErrorProvider nameErrorProvider = new ErrorProvider();
nameErrorProvider.SetIconAlignment(nameTextBox1, ErrorIconAlignment.MiddleRight);
nameErrorProvider.SetIconPadding(nameTextBox1, 2);
nameErrorProvider.BlinkRate = 1000;
nameErrorProvider.BlinkStyle = ErrorBlinkStyle.AlwaysBlink;

Upvotes: 0

user586399
user586399

Reputation:

You should take a look at C# Regex

Match match = Regex.Match(input, "^\d\d:\d\d$"));

if (!match.Success) MessageBox.Show("Error");

Upvotes: 0

JDB
JDB

Reputation: 25820

Check out the MaskedTextBox if you don't want to have to validate in the first place.

var l_control = new MaskedTextBox();
l_control.Mask = "00\:00";

If you want to make the first digit optional:

l_control.Mask = "90\:90";

Otherwise, you could use a regular expression. 4 digits separated by a colon would be: @"^\d{2}:\d{2}$". (The @ symbol prevents C# from treating '\' as an escape character - nothing unique to regex.)

Upvotes: 4

David
David

Reputation: 73554

There are three validation videos at http://windowsclient.net/learn/videos.aspx that will walk you through the whole process.

But using a Masked Textbox might be easier, depending on what you are collecting for data.

Heck, for what you're doing, you could be really safe and use two NumericUpDown controls and not have to deal with the validation at all.

Upvotes: 1

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