String Concatenation (VB.Net and ASP Classic Cross Reference Guide)

To concatenate two strings, use either the + or & operators. The & operator implicitly converts numbers. If you use the + operator to concatenate a string and a number, you have to cast the number as a string with CStr.

Alternatively, you can use the System.Text.StringBuilder class which frequently but not always provides faster code.

Dim FullName

Dim Age

//You can use + for strings.

FullName = "Prestwood"
Console.WriteLine("Hello " + FullName)

//For implicit casting, use &

Age = 35

Console.WriteLine(FullName & " is " & Age & " years old.")

'Implicit casting of numbers.

'

'This works:
MessageBox.Show(3.3)

'This fails:

'MessageBox.Show("" + 3.3)

'This works:
MessageBox.Show("" + CStr(3.3))

'Implicit casting &. This also works:

MessageBox.Show("" & 3.3)

Although you can use either a & or a + to concatenate values, my preference is to use a + because more languages use it. However, if you use & then some type conversions are done for you. If you use + you will sometimes have to cast a value to concatenate it. For example, you will have to use CStr to cast a number to a string if you use the + operator as a concatenation operator.

Dim FirstName
Dim LastName

FirstName  = "Mike"
LastName  = "Prestwood"

Response.Write "Full name: " & FirstName & " " + LastName

Response.Write "2+2=" + CStr(2+2)