Question

我有一些代码用数据库名称填充组合框。然后我有一个按钮，将名称保存回My.Settings并创建连接字符串。

这在很大程度上是有效的。如果我选择一个数据库，它将在我的表单中显示该数据库的正确信息，然后如果我返回到我的数据库选择器并执行相同操作，它仍将显示正确的设置。

问题是，我有一个重新加载datagridview sub，它重新填充网格。如果我选择一个数据库，然后退出并选择另一个，然后运行reload sub，它将从其他数据库中提取设置。即使它最初启动时，它在表单中也有正确的数据库信息。

我尝试了My.Settings.Reset和My.Settings.Save无济于事。

以下是一段代码：

Dim strDatabase As String = My.Settings.Database
Dim strDatabaseCon As String = My.Settings.DatabaseCon

Public Sub Loadcombobox()
    My.Settings.Reset()
    My.Settings.Save()
    Try

        Dim con As New SqlConnection(" Data Source=******\SQLEXPRESS; Initial Catalog =" & strDatabase & "; Integrated Security=true")
        con.Open()
        Dim cmd As New SqlCommand("Select * From sys.databases Where database_id > 4", con)
        Dim read As SqlDataReader = cmd.ExecuteReader()
        While read.Read()
            ComboBox1.Items.Add(read.Item(0))
        End While
        con.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    If ComboBox1.Text = "" Then
        MessageBox.Show("Please select a customer")
    Else


        My.Settings.Database = ComboBox1.Text

        strDatabase = My.Settings.Database

        My.Settings.DatabaseCon = "Data Source=******\SQLEXPRESS; Initial Catalog =" & strDatabase & "; Integrated Security=true"

        'Here we redeclare the strDatabaseCon = My.Settings.DatabaseCon
        strDatabaseCon = My.Settings.DatabaseCon

        My.Settings.Save()

        Mainform.Show()
        Me.Hide()
    End If
End Sub

此子表单的格式不同，导致datagridview从第一个数据库填充。

Sub ReloadRecords()
    Try
        FillDataGrid("SELECT * FROM Change_Control order by [DateOfChange] desc", dgvData)
        dgvData.Columns(0).Visible = False
        dgvData.Columns(1).Width = 200 ''Date of Change''
        dgvData.Columns(1).HeaderCell.Value = "Date Of Change"
        dgvData.Columns(2).Width = 200 ''Name''
        dgvData.Columns(2).HeaderCell.Value = "Who Made the Change"
        dgvData.Columns(3).Width = 470 ''Change made''
        dgvData.Columns(3).HeaderCell.Value = "Change Made"
        dgvData.Columns(4).Visible = False
    Catch ex As Exception
        MsgBox(ex.Message, MsgBoxStyle.Critical, Me.Text)
    End Try

End Sub

这是FillDataGrid函数

Dim strDatabaseCon As String = My.Settings.DatabaseCon
Public Function FillDataGrid(ByVal Sqlstring As String, ByVal MyDataGrid As DataGridView)
    Dim SQLCon As New SQLConnection(strDatabaseCon)
    Dim SQLAdapter As New SqlDataAdapter()
    Dim myDataset As New DataSet()

    SQLCon.Open()

    Try
        SQLAdapter.SelectCommand = New SqlCommand(Sqlstring, SQLCon)
        SQLAdapter.Fill(myDataset)
        MyDataGrid.DataSource = myDataset.Tables(0)
    Catch ex As Exception
    End Try

    SQLCon.Close()
    SQLAdapter.Dispose()
    myDataset.Dispose()
    Return True
End Function

Answer 1

不是很好的修复，但它解决了我的问题。

问题是我的FillDataGrid功能。不知道它的哪一部分，但我创建了一个新的功能，它现在没有用以前选择的数据库填充网格。

 Public Sub DisplayRecords()
    Try
        Dim da = New SqlDataAdapter("SELECT * from Change_Control order by [DateOfChange] desc", strDatabaseCon)
        dsetAssets = New DataSet
        da.Fill(dsetAssets, "Change_Control")
        dgvData.DataSource = dsetAssets.Tables("Change_Control").DefaultView
    Catch ex As Exception
        MsgBox(ex.Message, MsgBoxStyle.Critical, Me.Text)
    End Try

End Sub

VB.net - 动态数据库连接组合框

1 个答案: