IsNull Method

Visual Basic
C#

'Declaration
 
Public Overridable Function IsNull() As Boolean

'Usage
 
Dim instance As SuperEditBase
Dim value As Boolean
 
value = instance.IsNull()

public virtual bool IsNull()

Return Value

true if the control contains the null value; false otherwise

When this property returns true, the control contains the null value.

When the AllowNull property is set to true, the control accepts null values, and the user can provide a null value in the following ways:

Press F2.
Delete the contents of the control.
Call the SetNull method.
Call the ClearAll method.
Select the contents of the control and call the Clear method.

The AllowNull property must be set to true for the IsNull method and NullColor property to work correctly.

C#

privatevoidForm1_Load(objectsender,System.EventArgse)
{
control.AllowNull=true;
}

privatevoidcontrol_MouseDown(objectsender,System.Windows.Forms.MouseEventArgse)
{
boolbvalue;
bvalue=control.IsNull();
if(bvalue)
{
control.Value=500;
}
}

Visual Basic

PrivateSubForm1_Load(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesMyBase.Load
control.AllowNull=True
EndSub

PrivateSubcontrol_MouseDown(ByValsenderAsObject,ByValeAsSystem.Windows.Forms.MouseEventArgs)HandlesCurrency1.MouseDown
DimbvalueAsBoolean
bvalue=control.IsNull()
IfbvalueThen
control.Text=500
EndIf
EndSub

Target Platforms: Windows 2000 Professional (SP4), Windows 2000 Server, Windows 2003 Server (SP1), Windows 2008, Windows XP (SP2), Windows Vista, Windows 7, Windows 8

Reference

SuperEditBase Class
SuperEditBase Members
AllowNull Property
NullColor Property
SetNull Method
Text Property
Clear Method
ClearAll Method