方法的如果条件基于列表属性

Question

我有如下功能。我想使它更通用。希望能够发送数据列的参数和每个列的期望值。

Private Function SearchDtValue(dt As DataTable, Value1 As String, Value2 As String) As String 
    For Each row As DataRow In dt.Rows 
     If row("Name") = Value1 And row("Age") = Value2 Then 
      Return row("Surname") 
     End If 
    Next 
    Return Nothing 
End Function 

在我的新功能，可以让列及其价值观的不同势数进行检查，例如我想查询的数据表3列，并说每个要比较的3个预期值。在这种情况下，它看起来应该如下：

的伪代码：

SearchDtValue(dt as DataTable, dictionary(Of String, String),colNameValueToBeRetreived) 

所以词典（只是举例）将包含列名称和预期值的每一个。 在我们的例子中，当我送他们三个应该构建方法，例如这样：

如：

Dictionary could contain: 
    Age, 30 
    Name, John 
    Surname, Brzenk 

colNameValueToBeRetreived= Address 

方法应该是这样的基础上paraemters：

For Each row As DataRow In dt.Rows 
     If row(Age) = "30" And row(Name) = "John" And row(Surname) = "Brzenk" Then 
      Return row(colNameValueToBeRetreived) 
     End If 
    Next 

Answer 1

试试下面的代码。假设词典具有关键字作为列名称和值作为键的期望列值。

Private Function SearchDtValue(dt As DataTable, cols As Dictionary(Of String, String), colNameValueToBeRetreived As String) As String 
    Dim returnValue As String = Nothing 

    Try 
     Dim matchCount As Integer = 0 
     For Each row As DataRow In dt.Rows 
      For Each col In cols 
       If row(col.Key).ToString = col.Value Then 
        matchCount = matchCount + 1 
       End If 
      Next 

      If matchCount = cols.Count Then 
       returnValue = row(colNameValueToBeRetreived).ToString 
       Exit For 
      End If 
     Next 
    Catch ex As Exception 
     Throw New Exception("Error in matching column values") 
    End Try 

    Return returnValue 

End Function