If you want to append in C#, use
+= for short.
Code:
richTextBox1.Text += "appended value";
Much simpler/shorter than:
Code:
richTextBox1.Text = richTextBox1.Text + "appended value";
But both the same. In addition to +=, it should only really be used for smaller string concatenation. Larger string concatenation and you should be using the StringBuilder class because the ldstr operator isn't called more than once. What this means in terms of IL code is that you aren't rebuilding an entirely new string object to return a modified value. With the StringBuilder class you operate directly on the char data within the string and don't do anything more than what needs to be done to modify it's value, you aren't re-creating the entire string object over again.
Note that all these controls are actually still just Classes in the .NET framework. Therefore they have methods and properties like any other class, and a default constructor. The .Text, is actually a property that initializes the text field within that control.
