What is the difference between these three ways to

Question

I am bit confused between the below three ways to clear the contents of a textbox. I am working with WPF and found All are working, but I am unable to find the difference.

Can someone please explain to me about it with some examples?

• txtUserName.Clear();
• txtUserName.Text = string.Empty;
• txtUserName.Text = "";

Answer 1

Some say String.Empty is faster than "" however String.EMpty is Static member that is initialized to ""

When we call String.Empty the IL makes call to

mscorlib.dll 

IL_0007:  ldsfld     string [mscorlib]System.String::Empty

Whereas for "" it does not

IL_001a:  ldstr      ""

SO logically it would make more sense that "" is more efficient than String.Empty

Answer 2

Let's go through the commands one by one.

txtUserName.Clear();

The Clear() command assigns the texbox an empty string just like the next example. Source (best explination is given by syned on this point)

txtUserName.Text = string.Empty;

Now the string.Empty the actuall code for it is

static String()
{
    Empty = "";
}

Meaning that you assign the string "" after compile time.

txtUserName.Text = "";

Now here you just assign the "" string directly to the object on compile time.

Small side note txtUserName.Text = ""; is faster than txtUserName.Text = string.Empty; Source

Answer 3

"" creates an object while String.Empty creates no object. So it is more efficient to use String.Empty.

Refference: String.Empty vs ""

Regarding .Clear() i didnot get better answer then @syned's answer.

Answer 4

The string.Empty field is an empty string literal. It is slightly different from an empty string literal constant " ". There is a subtle difference—but one that could be significant in some scenarios. It changes the meaning of a program

We use string.Empty and "" in a C# program. The string.Empty field is initialized to "" at runtime by the .NET Framework.

You cannot use string.Empty as a switch case, because it cannot be determined at compile-time by the C# compiler.

Which explain the differences of string.empty and ""

The Clear() method does more than just remove the text from the TextBox. It deletes all content and resets the text selection