ErrObject.Number Property

Definition

Namespace:

Microsoft.VisualBasic

Assembly:

Microsoft.VisualBasic.Core.dll

Source:

ErrObject.vb

Returns or sets a numeric value specifying an error. Read/write.

public:
 property int Number { int get(); void set(int value); };

public int Number { get; set; }

member this.Number : int with get, set

Public Property Number As Integer

Property Value

Int32

Returns or sets a numeric value specifying an error. Read/write.

Exceptions

ArgumentException

Number is greater than 65535.

Examples

This example illustrates a typical use of the Number property in an error-handling routine.

    ' Typical use of Number property.
Sub test()
  On Error GoTo out

  Dim x, y As Integer
  x = 1 / y   ' Create division by zero error.
  Exit Sub
out:
  MsgBox(Err.Number)
  MsgBox(Err.Description)
  ' Check for division by zero error.
  If Err.Number = 11 Then
      y = y + 1
  End If
  Resume Next
End Sub

This example uses the Err object's Raise method to generate an original error within a function written in Visual Basic. The calling function can catch the error and report it to the user. Notice that procedure CallingProcedure contrasts the type of information that you can derive from an Err object with the information that you can derive from an Exception object.

Module Module1

    Const WidthErrorNumber As Integer = 1000
    Const WidthHelpOffset As Object = 100

    Sub Main()
        CallingProcedure()
    End Sub

    Sub TestWidth(ByVal width As Integer)
        If width > 1000 Then
            ' Replace HelpFile.hlp with the full path to an appropriate
            ' help file for the error. Notice that you add the error 
            ' number you want to use to the vbObjectError constant. 
            ' This assures that it will not conflict with a Visual
            ' Basic error.
            Err.Raise(vbObjectError + WidthErrorNumber, "ConsoleApplication1.Module1.TestWidth", 
                "Width must be less than 1000.", "HelpFile.hlp", WidthHelpOffset)
        End If
    End Sub

    Sub CallingProcedure()
        Try
            ' The error is raised in TestWidth.
            TestWidth(2000)
        Catch ex As Exception
            ' The Err object can access a number of pieces of
            ' information about the error.
            Console.WriteLine("Information available from Err object:")
            Console.WriteLine(Err.Number)
            Console.WriteLine(Err.Description)
            Console.WriteLine(Err.Source)
            Console.WriteLine(Err.HelpFile)
            Console.WriteLine(Err.HelpContext)
            Console.WriteLine(Err.GetException)

            Console.WriteLine(vbCrLf & "Information available from Exception object:")
            Console.WriteLine(ex.Message)
            Console.WriteLine(ex.ToString)

            Err.Clear()
        End Try
    End Sub
End Module

' The example produces the following output:
' Information available from Err object:
' -2147220504
' Width must be less than 1000.
' ConsoleApplication1.Module1.TestWidth
' HelpFile.hlp
' 100
' System.Exception: Width must be less than 1000.
'    at Microsoft.VisualBasic.ErrObject.Raise(Int32 Number, Object Source, Object
' Description, Object HelpFile, Object HelpContext)
'    at ConsoleApplication1.Module1.TestWidth(Int32 width) in C:\Users\example\App
' Data\Local\Temporary Projects\ConsoleApplication1\Module1.vb:line 17
'    at ConsoleApplication1.Module1.CallingProcedure() in C:\Users\example\AppData
' \Local\Temporary Projects\ConsoleApplication1\Module1.vb:line 25
'
' Information available from Exception object:
' Width must be less than 1000.
' System.Exception: Width must be less than 1000.
'    at Microsoft.VisualBasic.ErrObject.Raise(Int32 Number, Object Source, Object
' Description, Object HelpFile, Object HelpContext)
'    at ConsoleApplication1.Module1.TestWidth(Int32 width) in C:\Users\example\App
' Data\Local\Temporary Projects\ConsoleApplication1\Module1.vb:line 17
'    at ConsoleApplication1.Module1.CallingProcedure() in C:\Users\example\AppData
' \Local\Temporary Projects\ConsoleApplication1\Module1.vb:line 25

Remarks

All of the Raise arguments except Number are optional. If you omit optional arguments, and the property settings of the Err object contain values that have not been cleared, those values serve as the values for your error.

Because the Err object gives richer information than when you generate errors with the Error statement, Raise is useful for generating errors when writing class modules. For example, with the Raise method, the source that generated the error can be specified in the Source property, online Help for the error can be referenced, and so on.

When returning a user-defined error from an object, set Err.Number by adding the number you selected as an error code to the VbObjectError constant. For example, you use the following code to return the number 1051 as an error code:

Err.Raise(Number:=vbObjectError + 1051, Source:="SomeClass")

See also

• Err()
• ErrorToString()