Vb.net null test

This example uses the IsNull function to determine if a variable contains a Null. Have questions or feedback about Office VBA or this documentation? Please see Office VBA support and feedback for guidance about the ways you can receive support and provide feedback. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info. Contents Exit focus mode.

NET Framework, initial values are 0 or Nothing. NET program that uses module-level field Imports System. Nothing can be used with value types such as Integers.

When used on values, "Nothing" indicates the default value for the type. So an Integer assigned to Nothing is zero. Tip: Structures are too a value type. When we assign them to Nothing, we get an empty Structure with no bits set to 1. A string in VB. NET can be assigned to Nothing, which is the same concept as Null. We can test a Nothing String with the String. IsNullOrEmpty method. NET program that uses String. Nothing is not just like null in C.

Instead, it has a special behavior when used with value types—it acts like the default. Note: Thanks to Matthieu Penant for pointing out that Nothing has a separate meaning on value types.

Quote: In Visual Basic, if you set a variable of a non-nullable value type to Nothing, the variable is set to the default value for its declared type.

A reference that points to nothing can cause an Exception. An object may not exist. A reference may point to nothing. We use the literal Nothing to indicate a null, nil, nonexistent object.

If a reference may be Nothing, we must test before using its members. When a Module or Class is created, the fields within it are automatically set to Nothing. You never need to assign them to Nothing at creation time. Tip Variables in VB. NET never have garbage values. In managed code, like the. NET Framework, initial values are 0 or Nothing.

NET program that uses module-level field. Nothing can be used with value types such as Integers. When used on values, "Nothing" indicates the default value for the type.

So an Integer assigned to Nothing is zero. Tip Structures are too a value type. When we assign them to Nothing, we get an empty Structure with no bits set to 1.

A string in VB. NET can be assigned to Nothing, which is the same concept as Null. We can test a Nothing String with the String. IsNullOrEmpty method. Tip The term "null" is simply a different name for "Nothing.