Is an empty textbox considered an empty string or null?

The text box in question is involved in an if statement within my code, something to the effect of

if (textbox.text != "") 
{
    do this
}

I am curious if an empty text box will be considered an empty string or a null statement.

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Try to use IsNullOrWhiteSpace, this will make sure of validating the whitespace too without having to trim it.

if (!string.IsNullOrWhiteSpace(textbox.Text))
{
    //code here
}

According to documentation string.IsNullOrWhiteSpace evaluates to:

return String.IsNullOrEmpty(value) || value.Trim().Length == 0;

String.IsNullOrWhiteSpace:

Indicates whether a specified string is null, empty, or consists only of white-space characters.

Method 2

In short it will be an empty string, but you could use the debugger and check that yourself.

However for best practice use IsNullOrEmpty or IsNullOrWhiteSpace

if (!string.IsNullOrEmpty(textbox.Text)) {

}

Alternatively:

if (!string.IsNullOrWhiteSpace(textbox.Text)) {

}

http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx

Method 3

It will be an empty string but better to check with this IsNullOrEmpty or IsNullOrWhiteSpace

if (!string.IsNullOrEmpty(textbox.text))
{
  //do this
}

IsNullOrWhiteSpace is also take care of whitespace in input string. So if you don’t want to execute the code for whitespace too then use second option.

Method 4

It will be considered an empty string.

Method 5

string search = txtSearch.Text.Trim() != "" ? txtSearch.Text.Trim() : "0";

Method 6

if (textbox.text != “” || textbox.text != null)

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0