Writing Visual Basic Statements

A statement in Visual Basic is a complete instruction. It can contain keywords, operators, variables, constants, and expressions. Each statement belongs to one of the following three categories:

• Declaration statements, which name a variable, constant, or procedure and can also specify a data type.

  Writing Declaration Statements

• Assignment statements, which assign a value or expression to a variable or constant.

  Writing Assignment Statements

• Executable statements, which initiate actions. These statements can execute a method or function, and they can loop or branch through blocks of code. Executable statements often contain mathematical or conditional operators.

  Writing Executable Statements

Continuing a Statement over Multiple Lines

A statement usually fits on one line, but you can continue a statement onto the next line using a line-continuation character. In the following example, the MsgBox executable statement is continued over three lines:

Sub DemoBox()  'This procedure declares a string variable,
        ' assigns it the value Claudia, and then displays 
        ' a concatenated message.
    Dim myVar As String
    myVar = "John"
    MsgBox Prompt:="Hello " & myVar, _
        Title:="Greeting Box", _
        Buttons:=vbExclamation
End Sub

Adding Comments

Comments can explain a procedure or a particular instruction to anyone reading your code. Visual Basic ignores comments when it runs your procedures. Comment lines begin with an apostrophe (') or with Rem followed by a space, and can be added anywhere in a procedure. To add a comment to the same line as a statement, insert an apostrophe after the statement, followed by the comment. By default, comments are displayed as green text.

Checking Syntax Errors

If you press ENTER after typing a line of code and the line is displayed in red (an error message may display as well), you must find out what's wrong with your statement, and then correct it.