检查数据集是否包含特定值

Question

如何检查数据集是否包含特定值？以前没有人这么做过，真是太疯狂了。在网上找不到!!!

Answer 1

您的意思是遍历整个数据集表，列和行？

这可以帮到你：

Dim valueToSearch as String = "some text"
For Each dTable As DataTable In ds.Tables
    For Each dRow As DataRow In dTable.Rows
        For index As Integer = 0 To dTable.Columns.Count - 1
            Convert.ToString(dRow(index)).Contains(valueToSearch)
        Next
    Next
Next

Answer 2

假设我有包含表学生的数据集DsStu，其中包含列[Rollno，Name，Branch]。

案例1 我想要Rollno为15的学生姓名。

     Dim answer As String = ""
     Dim SerchRows() As Data.DataRow
     SerchRows = DsStu.Tables(0).Select("Rollno = '15'") 
     answer = ""

     For k As Integer = 0 To SerchRows.Length - 1
       If answer = "" then  
          answer = SerchRows(k).Item("Name")
       Else
          answer = answer & Vbnewline & SerchRows(k).Item("Name")
       End If
     Next

     MsgBox(" " & answer)

案例2 我想要Rollno大于等于15且分支是电气的所有学生的姓名。

     Dim answer As String = ""
     Dim SerchRows() As Data.DataRow

     SerchRows = DsStu.Tables(0).Select("Rollno >= '15' And Branch = 'Electrical'") 
     answer = ""

     For k As Integer = 0 To SerchRows.Length - 1
       If answer = "" then  
          answer = SerchRows(k).Item("Name")
       Else
          answer = answer & Vbnewline & SerchRows(k).Item("Name")
       End If
     Next

     MsgBox(" " & answer)

Answer 3

如果您使用的是BindingSource，请使用“查找”方法：http://msdn.microsoft.com/en-us/library/ms158165.aspx

因此，如果它返回-1则不存在，否则它将返回该位置。