Question

以下代码有什么问题。我不知道如何将sqldatabase表内容添加到下拉列表中请帮助

Protected Sub DropDownList3_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList3.SelectedIndexChanged

    Dim sqlcon As New SqlConnection("Data Source=SOf-22\SQLEXPRESS;Initial Catalog=Sales_oct_3;Persist Security Info=True;User ID=s;Password=121")


    If sqlcon.State = ConnectionState.Open Then
        sqlcon.Close()
    End If
    sqlcon.Open()
    Dim strcommand As String

    strcommand = "select item from tgnitem"
    Dim sqlcomm As New SqlCommand(strcommand, sqlcon)
    Dim o As String = sqlcomm.ExecuteNonQuery()

End Sub
End Class

Answer 1

你在做很多错事。对于简单的事情，您应该更好地坚持使用强类型的DataSet。它们会给你带来很多负担。您不需要维护连接，手动执行查询，遍历结果并将其填充到UI控件等中。了解有关类型化DataSet和简单绑定方案（例如您的）的更多信息，它们将为您带来长期利益。

使用类型化DataSet时，这种东西的简单4步机制是：

将新的DataSet添加到项目中。
通过右键单击DataSet设计器图面添加新的TableAdapter。编写您的查询，它将为您创建一个DataTable类型。您甚至可以使用服务器资源管理器拖动表。
将类型DataSet的实例添加到表单中。
将ComboBox的DataSource属性设置为此实例，将DataMember设置为DataTable的名称。将DisplayMember和ValueMember设置为DataTable的显示和值字段，例如DisplayMember =“Name”和ValueMember =“ItemID”。

Answer 2

看到这可能对你有帮助

Public Shared Function ClientList() As DataTable
    Dim dtResult As DataTable = Nothing
    Try
        Dim objDataLayer As New ClsDataLayer()
        objDataLayer.AddParameter("@REF_USER_ID", ClsCommons.IntUserId)
        dtResult = objDataLayer.ExecuteDataTable("TR_PROC_GetClientList")
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
    Return dtResult
End Function

Public Shared Sub ClientList(ByVal cmbClientList As ComboBox)
    cmbClientList.DropDownStyle = ComboBoxStyle.DropDownList
    Try
        Dim dtClientList As DataTable = ClsClientManager.ClientList()
        If ((Not IsNothing(dtClientList)) AndAlso dtClientList.Rows.Count > 0) Then
            Dim drClient As DataRow = dtClientList.NewRow()
            drClient(0) = -1
            drClient(1) = "< -- Select Department -- >"
            dtClientList.Rows.InsertAt(drClient, 0)
            cmbClientList.DataSource = dtClientList
            cmbClientList.DisplayMember = "CLIENT_NAME"
            cmbClientList.ValueMember = "CLIENT_ID"
        Else
            MessageBox.Show("There is no Department to load", "Talent Recruit", MessageBoxButtons.OK, MessageBoxIcon.Information)
        End If
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Sub

将sql数据库表内容填充到dropdownlist中

2 个答案: