Recordset.NoMatch-Eigenschaft (DAO)

Gilt für: Access 2013, Office 2013

Gibt an, ob ein bestimmter Datensatz mithilfe der Seek-Methode oder einer der Find-Methoden gefunden wurde (nur Microsoft Access-Arbeitsbereiche).

Syntax

Ausdruck .NoMatch

Ausdruck Eine Variable, die ein Recordset-Objekt darstellt.

Bemerkungen

Wenn Sie ein Recordset-Objekt öffnen oder erstellen, hat seine NoMatch-Eigenschaft den Wert False.

To locate a record, use the Seek method on a table-type Recordset object or one of the Find methods on a dynaset- or snapshot-type Recordset object. Check the NoMatch property setting to see whether the record was found.

Wenn die Methoden Seek und Find nicht erfolgreich sind und die NoMatch-Eigenschaft den Wert True hat, ist der aktuelle Datensatz nicht mehr gültig. Rufen Sie die Textmarke des aktuellen Datensatzes ab, bevor Sie die Seek- oder Find-Methode verwenden, wenn Sie zu diesem Datensatz zurückkehren müssen.

Hinweis

Das Verwenden einer der Move-Methoden für ein Recordset-Objekt hat keinen Einfluss auf die Einstellung seiner NoMatch-Eigenschaft.

Beispiel

This example uses the NoMatch property to determine whether a Seek and a FindFirst were successful, and if not, to give appropriate feedback. The SeekMatch and FindMatch procedures are required for this procedure to run.

    Sub NoMatchX() 
     
       Dim dbsNorthwind As Database 
       Dim rstProducts As Recordset 
       Dim rstCustomers As Recordset 
       Dim strMessage As String 
       Dim strSeek As String 
       Dim strCountry As String 
       Dim varBookmark As Variant 
     
       Set dbsNorthwind = OpenDatabase("Northwind.mdb") 
       ' Default is dbOpenTable; required if Index property will  
       ' be used. 
       Set rstProducts = dbsNorthwind.OpenRecordset("Products") 
     
       With rstProducts 
          .Index = "PrimaryKey" 
     
          Do While True 
             ' Show current record information; ask user for  
             ' input. 
             strMessage = "NoMatch with Seek method" & vbCr & _ 
                "Product ID: " & !ProductID & vbCr & _ 
                "Product Name: " & !ProductName & vbCr & _ 
                "NoMatch = " & .NoMatch & vbCr & vbCr & _ 
                "Enter a product ID." 
             strSeek = InputBox(strMessage) 
             If strSeek = "" Then Exit Do 
     
             ' Call procedure that seeks for a record based on  
             ' the ID number supplied by the user. 
             SeekMatch rstProducts, Val(strSeek) 
          Loop 
     
          .Close 
       End With 
     
       Set rstCustomers = dbsNorthwind.OpenRecordset( _ 
          "SELECT CompanyName, Country FROM Customers " & _ 
          "ORDER BY CompanyName", dbOpenSnapshot) 
     
       With rstCustomers 
     
          Do While True 
             ' Show current record information; ask user for  
             ' input. 
             strMessage = "NoMatch with FindFirst method" & _ 
                vbCr & "Customer Name: " & !CompanyName & _ 
                vbCr & "Country: " & !Country & vbCr & _ 
                "NoMatch = " & .NoMatch & vbCr & vbCr & _ 
                "Enter country on which to search." 
             strCountry = Trim(InputBox(strMessage)) 
             If strCountry = "" Then Exit Do 
     
             ' Call procedure that finds a record based on  
             ' the country name supplied by the user. 
             FindMatch rstCustomers, _ 
                "Country = '" & strCountry & "'" 
          Loop 
     
          .Close 
       End With 
     
       dbsNorthwind.Close 
     
    End Sub 
     
    Sub SeekMatch(rstTemp As Recordset, _ 
       intSeek As Integer) 
     
       Dim varBookmark As Variant 
       Dim strMessage As String 
     
       With rstTemp 
          ' Store current record location. 
          varBookmark = .Bookmark 
          .Seek "=", intSeek 
     
          ' If Seek method fails, notify user and return to the  
          ' last current record. 
          If .NoMatch Then 
             strMessage = _ 
                "Not found! Returning to current record." & _ 
                vbCr & vbCr & "NoMatch = " & .NoMatch 
             MsgBox strMessage 
             .Bookmark = varBookmark 
          End If 
     
       End With 
     
    End Sub 
     
    Sub FindMatch(rstTemp As Recordset, _ 
       strFind As String) 
     
       Dim varBookmark As Variant 
       Dim strMessage As String 
     
       With rstTemp 
          ' Store current record location. 
          varBookmark = .Bookmark 
          .FindFirst strFind 
     
          ' If Find method fails, notify user and return to the  
          ' last current record. 
          If .NoMatch Then 
             strMessage = _ 
                "Not found! Returning to current record." & _ 
                vbCr & vbCr & "NoMatch = " & .NoMatch 
             MsgBox strMessage 
             .Bookmark = varBookmark 
          End If 
     
       End With 
     
    End Sub 

Im folgenden Beispiel wird gezeigt, wie Sie mithilfe der Seek-Methode einen Datensatz in einer verknüpften Tabelle finden.

Der Beispielcode stammt von:Microsoft Access 2010 Programmer's Reference.

    Sub TestSeek()
        ' Get the path to the external database that contains
        ' the tblCustomers table we're going to search.
        Dim strMyExternalDatabase
        Dim dbs    As DAO.Database
        Dim dbsExt As DAO.Database
        Dim rst    As DAO.Recordset
        Dim tdf    As DAO.TableDef
        
        Set dbs = CurrentDb()
        Set tdf = dbs.TableDefs("tblCustomers")
        strMyExternalDatabase = Mid(tdf.Connect, 11)
        
        'Open the database that contains the table that is linked
        Set dbsExt = OpenDatabase(strMyExternalDatabase)
        
        'Open a table-type recordset against the external table
        Set rst = dbsExt.OpenRecordset("tblCustomers", dbOpenTable)
        
        'Specify which index to search on
        rst.Index = "PrimaryKey"
        
        'Specify the criteria
        rst.Seek "=", 123
        
        'Check the result
        If rst.NoMatch Then
            MsgBox "Record not found."
        Else
            MsgBox "Customer name: " & rst!CustName
        End If
        
        rst.Close
        dbs.Close
        dbsExt.Close
        Set rst = Nothing
        Set tdf = Nothing
        Set dbs = Nothing
        
        
    End Sub