Question

我试图根据列匹配从数据表中删除行。但是得到如下错误：

Collection was modified; enumeration operation might not execute

我的代码如下：

Dim dt As DataTable = CType(ViewState("SavedAccount"), DataTable)
        Dim dtTemp As DataTable = dt
        Dim count As Integer = 0
        Dim row As GridViewRow = gvAccountList.Rows(e.RowIndex)
        Dim lblAccountName As Label = CType(row.FindControl("lblAccntName"), Label)
        For Each dr As DataRow In dt.Rows


            If dr("Account_Name") = lblAccountName.Text.Trim Then


                dr.Delete()


            End If
            count = count + 1
        Next

        ViewState("SavedAccount") = dt

        AddRowInGridview()

我做错了什么？看起来很简单！

Answer 1

在枚举枚举时，无法修改枚举。您可以通过索引循环：

    For index = 0 To dt.Rows.Count - 1
        If dt.Rows(index)("Account_Name") = lblAccountName.Text.Trim() Then
            dt.Rows(index).Delete()
        End If
    Next

Answer 2

dr.Delete()

实际上并没有从DataTable中删除该行，而是使用

For Each dr As DataRow In dt.Rows


        If dr("Account_Name") = lblAccountName.Text.Trim Then


            dt.Delete(dr);


        End If
        count = count + 1
    Next

Answer 3

我通过以下方式解决了这个问题：

  Dim dt As DataTable = CType(ViewState("SavedAccount"), DataTable)
        Dim dtTemp As DataTable = dt
        Dim count As Integer = 0
        Dim row As GridViewRow = gvAccountList.Rows(e.RowIndex)
        Dim lblAccountName As Label = CType(row.FindControl("lblAccntName"), Label)
        Dim drow As DataRow()
        drow = dt.Select("Account_Name='" + lblAccountName.Text.Trim + "'")
        For i As Integer = 0 To drow.Length - 1
            dt.Rows.Remove(drow(i))
        Next

Answer 4

尝试一下

For i = 0 To dt.Rows.Count - 1
     'DO ....  then delete....
     dt.Rows(0).Delete()
Next

无法从每个循环的数据表中删除行

4 个答案: