Information.IsDBNull(Object) Method

Reference

Definition

Namespace:: Microsoft.VisualBasic

Assembly:: Microsoft.VisualBasic.Core.dll

Assembly:: Microsoft.VisualBasic.dll

Source:: Information.vb

Source:: Information.vb

Source:: Information.vb

Important

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Returns a Boolean value indicating whether an expression evaluates to the DBNull class.

public:
 static bool IsDBNull(System::Object ^ Expression);

public static bool IsDBNull(object? Expression);

public static bool IsDBNull(object Expression);

static member IsDBNull : obj -> bool

Public Function IsDBNull (Expression As Object) As Boolean

Parameters

Expression: Object

Required. Object expression.

Returns

Boolean

Returns a Boolean value indicating whether an expression evaluates to the DBNull class.

Examples

This example uses the IsDBNull function to determine if a variable evaluates to DBNull.

Dim testVar As Object
Dim nullCheck As Boolean
nullCheck = IsDBNull(testVar)
testVar = ""
nullCheck = IsDBNull(testVar)
testVar = System.DBNull.Value
nullCheck = IsDBNull(testVar)
' The first two calls to IsDBNull return False; the third returns True.

Remarks

IsDBNull returns True if the data type of Expression evaluates to the DBNull type; otherwise, IsDBNull returns False.

The System.DBNull value indicates that the Object represents missing or nonexistent data. DBNull is not the same as Nothing, which indicates that a variable has not yet been initialized. DBNull is also not the same as a zero-length string (""), which is sometimes referred to as a null string.

Applies to

Product	Versions
.NET	Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

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