How can I check textbox is begining only alphabets?

Question

I want to start with alphabet in textbox. How can I check textbox is begining only alphabets ? For example:

N4534 -- True
NN435 -- True
2N645 -- False
?N645 -- False

Thanks

I think you could use regular expression [Regular expression on TextBox in WPF](http://stackoverflow.com/questions/1734511/how-can-i-set-regular-expression-on-textbox) — cat916, Apr 19 '13 at 13:31

score 10 · Answer 1 · answered Apr 19 '13 at 13:29

10

try this

string str = "N4535";
bool isLetter = !String.IsNullOrEmpty(str) && Char.IsLetter(str[0]);

answered Apr 19 '13 at 13:29

Jhonatas Kleinkauff

956
7
18

score 0 · Answer 2 · answered Apr 19 '13 at 14:09

0

    string input = "N4534 ";

    Regex reg = new Regex("^[a-zA-z].*$"); 

    // Match the input and write results
    Match match = reg.Match(input);

    return match.Success;

answered Apr 19 '13 at 14:09

Mudassir Hasan

28,083
20
99
133

score 0 · Answer 3 · answered Apr 19 '13 at 15:35

1> Create a behaviour as shown here

2> Subscribe to TextChanged event.

3> Apply RegEx (E.g. "^[a-zA-z].*$")

4> clear text if RegEx return false.

<TextBox Text="{Binding ...}" >
  <e:Interaction.Behaviors>
    <b:AlphaTextBehavior/>
 </e:Interaction.Behaviors>
</TextBox>

public class DragBehavior : Behavior<TextBox>
{

    protected override void OnAttached()
    {
      // AssociatedObject.TextChanged += 
    }
}

How can I check textbox is begining only alphabets?

3 Answers3