What is the difference between (“”) and (null)

Question

While trying to set Validations i initially encountered some problems with checking if a textbox is null, i tried using

    private void btnGo_Click(object s         


        

Answer 1

The System.String data type in .NET is a class, a reference type. So an empty string ("" or string.Empty) is a reference to a value with zero length, while null does not reference a to real value, so any attempt to access the value it references will fail.

For example:

string emptyString = "";
string nullString = null;

Console.WriteLine(emptyString.Length); // 0
Console.WriteLine(nullString.Length);  // Exception!

I'd recommend you use IsNullOrEmpty (or IsNullOrWhiteSpace) in your validation code, to handle both cases:

if (string.IsNullOrEmpty(name))
{
     labelError.Visiblle = true;
     labelError.Text = "Field Cannot be Left Blank"
}