A string is an object of type System.String whose value is text. Internally, the text is stored as a sequential read-only collection of Char objects.
Length of a string represents the number of Char objects it contains, not the number of Unicode characters.The string declaration and initialization can be done in different ways.
You can declare the string variable without initialization, as shown below.
Dim str1 As String
You can declare and initialize a string variable to Nothing.
Dim str2 As String = Nothing
You can also declare and initialize a string variable to an empty string, use the Empty constant instead of the literal "".
Dim str3 As String = String.Empty
To declare and initialize a string variable with a regular string literal.
Dim sqlServerPath As String = "C:\Program Files (x86)\Microsoft SQL Server"
To declare and initialize a string variable with a verbatim string literal.
Dim vsPath As String = "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community"
In local variables, you can use implicit typing.
Dim str4 = "It is a sample message of a strongly-typed System.String!"
You can use a const string to prevent it from being used to store another string value.
Const str5 As String = "You can't change me now"
If you try to assign another value to the str5 which is constant, you will see an error.
You can use the String constructor only when creating a string from a char*, char[], or sbyte*.
Dim letters As Char() = {"A", "B", "C"}
Dim alphabet As String = New String(letters)
You can concatenate multiple string variables using the & operator.
Dim firstName As String = "John "
Dim lastName As String = "Doe"
Dim name As String = firstName & lastName
A text in the real world can include any character such as double quote ("), single quote ('), etc. In C#, a string is surrounded with double quotes, you can't include these special characters include in a string directly. To use them in a string, you will need to include escaping character \ (backslash) before these special characters.
| Escape sequence | Character |
|---|---|
| ' | Single quote |
| " | Double quote |
| \ | Backslash |
| \0 | Null |
| \a | Alert |
| \b | Backspace |
| \f | Form feed |
| \n | New line |
| \r | Carriage return |
| \t | Horizontal tab |
| \v | Vertical tab |
Dim text As String = "This is a ""string"" in C#."