Visual Studio 2015 VB.net如何在MS Access數據庫中查找記錄並禁用表單中的按鈕？

Question

我正在嘗試加載表單，但是在加載時必須轉到Access數據庫，並檢查是否存在帶有按鈕文本和今天日期的記錄，如果存在，則禁用按鈕。 我的表單中有大約50個按鈕。 注意：請檢查以下我的代碼，它們適用於4或5，但其他代碼不起作用。 我沒有錯誤信息。 也許如果有人有更好的方法可以做到這一點，我將非常感謝。 這是我的加載表格

Imports System.Data.OleDb

公共類Wells Dim提供程序作為字符串Dim數據文件作為字符串Dim connString作為字符串公共myConnection作為OleDbConnection = New OleDbConnection公共dr作為OleDbDataReader公共da As OleDbDataAdapter Dim錯誤作為字符串

Private Sub Wells_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    lblUserActive.Text = UserActive
    ZoneActive = Nothing
    WellActive = Nothing

    provider = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source ="
    dataFile = "f:\wortendyke\WortendykeTables.accdb"
    connString = provider & dataFile
    myConnection.ConnectionString = connString
    Errors = ""

    Try
        If Button19.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button19.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button19.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button19.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try


    Try
        If Button23.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button23.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button23.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button23.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button17.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button17.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button17.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button17.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button3.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button3.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button3.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button3.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try
    Try
        If Button20.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button20.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button20.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button20.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button1.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button1.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button1.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button1.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button2.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button2.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button2.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button2.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button18.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button18.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button18.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button18.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button7.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button7.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button7.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button7.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button16.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button16.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button16.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button16.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button15.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button15.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button15.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button15.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button14.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button14.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button14.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button14.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button13.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button13.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button13.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button13.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button12.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button12.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button12.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button12.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button11.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button11.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button11.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button11.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button10.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button10.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button10.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button10.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button9.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button9.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button9.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button9.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button8.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button8.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button8.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button8.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button6.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button6.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button6.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button6.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button5.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button5.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button5.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button5.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try

    Try
        If Button4.Enabled = True Then

            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM maintable WHERE location='" & Button4.Text & "' AND pumpingdate=#" & dateActive & "#"
            Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
            dr = cmd.ExecuteReader
            dr.Read()
            If Button4.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
                Button4.Enabled = False
                myConnection.Close()
                Me.Refresh()
            End If

        End If

    Catch ex As Exception

    End Try



End Sub

Answer 1

您需要在catch塊中添加一些內容，以便查看錯誤消息

Try
    If Button4.Enabled = True Then

        myConnection.Open()
        Dim str As String
        str = "SELECT * FROM maintable WHERE location='" & Button4.Text & "' AND pumpingdate=#" & dateActive & "#"
        Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
        dr = cmd.ExecuteReader
        dr.Read()
        If Button4.Text = dr("location").ToString And dateActive = dr("pumpingdate").ToString Then
            Button4.Enabled = False
            myConnection.Close()
            Me.Refresh()
        End If

    End If

Catch ex As Exception
  msgbox(ex.tostring)
End Try

這樣就可以看到問題所在

就更好的方法而言，您可以通過幾種方法做到這一點，其中大多數方法將更加高效且易於維護。 但是我建議的第一件事是將數據邏輯與顯示邏輯分開，例如，創建一個函數，如果應該禁用按鈕，則該函數返回一個布爾值

Public function isDisabled(ButtonName as string, dateActive as date) as boolean
   Dim retval as boolean = false
    myConnection.Open()
        Dim str As String
        str = "SELECT * FROM maintable WHERE location='" & ButtonName & "' AND pumpingdate=#" & dateActive & "#"
        Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
        dr = cmd.ExecuteReader
        dr.Read()

        if dr.rows.count > 0 then  
            retval = true 
        else
            retval = false 
        end if 
        myConnection.Close()

        return retval
  end function

然后，您可以在負載上執行類似的操作

 try
    if button4.enabled =true then 
        button4.enabled = isdisabled(button4.text, activedate)
    end if 
 catch exp as exception
    msgbox(exp.tostring)
 end if 

還有很多，但這只是一個開始

*某些語法可能是錯誤的，我是從手機的內存中執行此操作的