Question

我有以下子程序：

 Private Sub Exceptionquery()
        Dim connection As System.Data.SqlClient.SqlConnection
        Dim connectionString As String = "Initial Catalog=mdr;Data Source=xxxxx;uid=xxxxx;password=xxxxx"
        Dim _sql As String = "SELECT [Exceptions].Employeenumber,[Exceptions].exceptiondate, [Exceptions].starttime, [exceptions].endtime, [Exceptions].code, datediff(minute, starttime, endtime)  as duration INTO scratchpad3 " + _
        "FROM [Exceptions]" + _
        "where [Exceptions].exceptiondate between @payperiodstartdate and payperiodenddate" + _
"GROUP BY [Exceptions].Employeenumber, [Exceptions].Exceptiondate, [Exceptions].starttime, [exceptions].endtime," + _
"[Exceptions].code, [Exceptions].exceptiondate"
        connection = New SqlConnection(connectionString)
        connection.Open()
        Dim _CMD As SqlCommand = New SqlCommand(_sql, connection)
        _CMD.Parameters.AddWithValue("@payperiodstartdate", payperiodstartdate)
        _CMD.Parameters.AddWithValue("@payperiodenddate", payperiodenddate)
        connection.Close()
    End Sub
    Public Sub exceptionsButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exceptionsButton.Click
        Exceptionquery()
        Dim connection As System.Data.SqlClient.SqlConnection
        Dim adapter As System.Data.SqlClient.SqlDataAdapter = New System.Data.SqlClient.SqlDataAdapter
        Dim connectionString As String = "Initial Catalog=mdr;Data Source=xxxxx;uid=xxxxx;password=xxxxx"
        Dim ds As New DataSet
        Dim _sql As String = "SELECT * from scratchpad3"
        connection = New SqlConnection(connectionString)
        connection.Open()
        Dim _CMD As SqlCommand = New SqlCommand(_sql, connection)
        _CMD.Parameters.AddWithValue("@payperiodstartdate", payperiodstartdate)
        _CMD.Parameters.AddWithValue("@payperiodenddate", payperiodenddate)
        adapter.SelectCommand = _CMD
        Try
            adapter.Fill(ds)
            If ds Is Nothing OrElse ds.Tables.Count = 0 OrElse ds.Tables(0).Rows.Count = 0 Then
                'it's empty
                MessageBox.Show("There was no data for this time period. Press Ok to continue", "No Data")
                connection.Close()
                Exceptions.saveButton.Enabled = False
                Exceptions.Show()
            Else
                connection.Close()
                Exceptions.Show()
            End If

        Catch ex As Exception
            MessageBox.Show(ex.ToString)
            connection.Close()
        End Try
    End Sub

当我按下按钮时：

Public Sub exceptionsButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exceptionsButton.Click

我的子程序Exceptionquery没有被解雇。我知道这可能是一件很简单的事情，但我不知道它是什么。有人可以帮我解决这个问题吗？

谢谢

Answer 1

你确定ExceptionQuery（）是从exceptionsButton_Click运行的吗？您显示的示例应该有效。单步执行调试器并验证您的按钮事件是否实际触发。

Answer 2

它应该工作，检查是否完全调用了事件处理程序exceptionsButton_Click，如果执行进入它，则查看断点。

P.S。 一个非常重要的小细节：您处理连接的方式不是最佳的，您可以使用using块，如下所示：

using (dim connection as New SqlConnection(connectionString)

...

通过这种方式，你确定连接已经关闭并在耗尽范围时被处理掉，并且你不需要if / else和catch中的所有那些connection.close，无论如何你到目前为止都是错误的，因为如果连接已关闭，您进入捕获并尝试再次关闭它，将出现另一个错误。

子程序没有触发

2 个答案: