The body of a text message contains a string.
After an application creates an text message, the body of the message is readable and writable. The body remains readable and writable after the application sends the message. When an application receives an text message, the body of the message is read-only. If an application calls the Clear Body method of the Message class for C or C++ or of the IMessage interface for .NET when the body of an text message is read-only, the body becomes readable and writable. The method also clears the body.