Check Whether a TextBox is empty or not

c# wpf string validation user-input
user5683768 picture user5683768 · Dec 15, 2015 · Viewed 74.1k times · Source

I have a TextBox. And I want to check if it's empty.

Which way is better

if(TextBox.Text.Length == 0)

or

if(TextBox.Text == '')

?

Answer

Fᴀʀʜᴀɴ Aɴᴀᴍ picture Fᴀʀʜᴀɴ Aɴᴀᴍ · Dec 15, 2015

You should use String.IsNullOrEmpty() to make sure it is neither empty nor null (somehow):

if (String.IsNullOrEmpty(textBox1.Text))
{
    // Do something...
}

More examples here.

For practical purposes you might also consider using String.IsNullOrWhitespace() since a TextBox expecting whitespace as input probably negates any purpose, except in case of, say, letting the user pick a custom separator for stuff.

Related questions

adding a ListBoxItem in a ListBox in C#?

I know that: String test = "test"; ListBox.Items.Add(test); or String test = "test"; int index = 1; ListBox.Items.Insert(index, String); adds the String in a ListBox, but I want to insert ListBoxItem, how to? previously I learn that var …

Read More
Metadata file '.dll' could not be found

I am working on a WPF, C# 3.0 project, and I get this error: Error 1 Metadata file 'WORK=- \Tools\VersionManagementSystem\BusinessLogicLayer\bin\Debug \BusinessLogicLayer.dll' could not be found C:\-=WORK=- \Tools \VersionManagementSystem\VersionManagementSystem\CSC VersionManagementSystem This is …

Read More
Binding a WPF ComboBox to a custom list

I have a ComboBox that doesn't seem to update the SelectedItem/SelectedValue. The ComboBox ItemsSource is bound to a property on a ViewModel class that lists a bunch of RAS phonebook entries as a CollectionView. Then I've bound (at separate …

Read More