keep web form drop down list from chagning

Question

User1929727834 posted

In a vb.net 2012 web form application, there is a page that is only accessed by the administrators of the application.
There are 2 drop down list options for the user to select and one submit button. Basically one drop donw list is the language that
is to be selected and the kind of letter that is to be generated. The letter is a 'template' generic letter that the administrator changes.
After the administrator hits the submit button, the template letter is changed in the database and one dropdown list shows the language that
was selected. The problem is the kind of letter drop list does not stay and show what was selcted. The kind of letter drop down lists displays
what the intitial drop down list looked like initially.

Thus would you show me how to keep is the kind of letter drop down list from changing once the user clicks the submit button?

Answer 1

User2053451246 posted

Show the code that runs when the Submit button is clicked as well as any page load events.

Answer 2

User665608656 posted

Hi dcofomaha,

According to your description,I can't understand your question clearly.

Is user and administrator the same role?

If not, I suggest that you store the value of the letter drop list selected by the current user through the database when the administrator click the submit button, and then when the user logs in, he needs to get the corresponding value in the database and let the letter drop list automatically reverse the value.

If it's the same role, I suggest that you use Session to store the index selected by your letter drop list. By clicking the submit button, you can get the session value and change the selection index of the letter drop list to the index selected before clicking the button (that is, the value stored in the session).

Here is an example used by Session:

<form id="form1" runat="server">
        <div>
            <asp:DropDownList ID="DropDownList1" runat="server" ></asp:DropDownList>
            <asp:Button ID="Button1" runat="server" Text="Submit" OnClick="Button1_Click" />
            <br />
            <asp:DropDownList ID="DropDownList2" runat="server"  OnSelectedIndexChanged="DropDownList2_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>
        </div>
    </form>

code behind:

Class SurroundingClass
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        If Not IsPostBack Then
            DropDownList1.DataSource = BindData1()
            DropDownList1.DataTextField = "Language"
            DropDownList1.DataValueField = "Language"
            DropDownList1.DataBind()
            DropDownList2.DataSource = BindData2(DropDownList1.Text.ToString())
            DropDownList2.DataTextField = "Letter"
            DropDownList2.DataValueField = "Letter"
            DropDownList2.DataBind()
            Session("selectIndex") = 0
        End If
    End Sub

    Private Function BindData2(ByVal Language As String) As DataTable
        Dim connectionString As String = ConfigurationManager.ConnectionStrings("TestConnectionString1").ConnectionString
        Dim strSql As String = "select Letter from Language where Language =@Language"
        Dim parameters As SqlParameter() = {New SqlParameter("@Language", Language)}

        Using connection As SqlConnection = New SqlConnection(connectionString)

            Using cmd As SqlCommand = New SqlCommand(strSql, connection)

                For Each parameter As SqlParameter In parameters
                    cmd.Parameters.Add(parameter)
                Next

                Try
                    connection.Open()
                    Dim da As SqlDataAdapter = New SqlDataAdapter(cmd)
                    Dim ds As DataSet = New DataSet()
                    da.Fill(ds)
                    Return ds.Tables(0)
                Catch ex As SqlException
                    Throw New Exception(ex.Message)
                Finally
                    connection.Close()
                End Try
            End Using
        End Using
    End Function

    Private Function BindData1() As DataTable
        Dim connectionString As String = ConfigurationManager.ConnectionStrings("TestConnectionString1").ConnectionString
        Dim strSql As String = "select distinct Language from Language"

        Using connection As SqlConnection = New SqlConnection(connectionString)

            Using cmd As SqlCommand = New SqlCommand(strSql, connection)

                Try
                    connection.Open()
                    Dim da As SqlDataAdapter = New SqlDataAdapter(cmd)
                    Dim ds As DataSet = New DataSet()
                    da.Fill(ds)
                    Return ds.Tables(0)
                Catch ex As SqlException
                    Throw New Exception(ex.Message)
                Finally
                    connection.Close()
                End Try
            End Using
        End Using
    End Function

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
        DropDownList2.DataSource = BindData2(DropDownList1.SelectedItem.Text.ToString())
        DropDownList2.DataBind()
        DropDownList2.DataValueField = "Letter"
        DropDownList2.DataTextField = "Letter"
        DropDownList2.SelectedIndex = Convert.ToInt32(Session("selectIndex"))
    End Sub

    Protected Sub DropDownList2_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
        Session("selectIndex") = DropDownList2.SelectedIndex
    End Sub
End Class

The result of my work demo:    

   

Best Regards,

YongQing.