本文介绍了Visual Studio 2015 VB.net 如何在 MS Access 数据库中查找记录并禁用表单中的按钮?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试加载表单，但加载时必须转到访问数据库并检查是否存在带有按钮文本和今天日期的记录，如果存在则禁用该按钮.我在表单中有大约 50 个按钮.注意:检查下面我的代码，它们适用于 4 或 5，但其他的不起作用.我没有错误信息.也许如果有人有更好的方法来做到这一点，我将非常感谢.这是我的加载表单
i am trying to load a form, but when loading must go to a access database and check if a record with the button text and today date exist, if it exist then disable the button. I have about 50 button in the form. NOTE: check my codes below, they works for 4 or 5 but the other ones not working. i have no error message. Maybe if someone have a better way to do this i will be very thanks full .This is my loading form
Imports System.Data.OleDb
公共课井Dim provider As StringDim dataFile As StringDim connString As StringPublic myConnection As OleDbConnection = New OleDbConnection公共博士 As OleDbDataReader公共数据作为 OleDbDataAdapter将错误淡化为字符串
Public Class Wells Dim provider As String Dim dataFile As String Dim connString As String Public myConnection As OleDbConnection = New OleDbConnection Public dr As OleDbDataReader Public da As OleDbDataAdapter Dim Errors As String
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
推荐答案
您需要向 catch 块添加一些内容，以便您可以看到错误消息
You need to add something to you catch block so you can see the error messages
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
这样你就可以看到问题所在了
That way you can see what the problem is
就更好的方式而言，您可以通过几种方式来实现，其中大多数方式会更高效且更易于维护.但我建议的第一件事是将您的数据逻辑与显示逻辑分开，例如创建一个函数，如果按钮被禁用，则返回一个布尔值
As far as a better way, you could do that a couple ways, most of them would be more efficient and easier to maintain. But the first thing I would suggest is separating your data logic from your display logic for example create a function that returns a boolean if a button is suppose to be disabled
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
然后你可以在你的负载上做这样的事情
Then you can do something like this on your load
try
if button4.enabled =true then
button4.enabled = isdisabled(button4.text, activedate)
end if
catch exp as exception
msgbox(exp.tostring)
end if
还有很多，但这是一个开始
There is alot more but that's a start
*有些语法可能是错误的，我是在手机上凭记忆做到的
*Some of the syntax might be wrong I'm doing this from memory on a phone
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