使用 DLookup 函數可以方便實現此功能,參考代碼如下:
Option?Compare?DatabasePublic?Function?SafeDLookup(ByVal?Expr?As?String,?_
ByVal?Domain?As?String,?_
Optional?Criteria?As?Variant)?As?Variant
SafeDLookup?=?Null
On?Error?Resume?Next
If?IsMissing(Criteria)?Then
SafeDLookup?=?DLookup(Expr,?Domain)
Else
SafeDLookup?=?DLookup(Expr,?Domain,?Criteria)
End?If
End?Function
Private?Sub?Command2_Click()
Dim?varC?As?Variant
Dim?varBID?As?Variant
varBID?=?BID.Value
varC?=?SafeDLookup("C",?"A",?"B='"?&?Replace(varBID,?"'",?"''")?&?"'")
If?Not?IsNull(varC)?Then
MsgBox?varBID?&?"已被"?&?varC?&?"借走"
End?If
End?Sub
假設 A 表中有如下測試數據:
當在 BID 文本框中輸入 k137 時的運行效果: