Store DropDownList selection in session for use as scalar in SQL query on postback.

[Alex Jermy]

Hi,

I have a Drop Down List that is populated from a remote SQL database via a SqlDatasource control. The Drop Down List has an automatic selection which is used to populate 3 charts with data on page load. I want the user to be able to change the selection in the Drop Down List, and to store this as a session variable so that I can use it in codebehind as a scalar for the SQL query to repopulate the chart with the user's selection. Is this possible or is there a better way to populate the charts using the user's selection?

I have attached my ASP file and C# file below.

Thanks,

Alex

Attachment: PlanningAnalysis_3f2fc2d1.zip

[Christopher Issac Sunder K]

Hi Alex,  

Greetings from Syncfusion support. 

We suggest you to store the selected value in a session variable through “OnValueChange” event of DropDownList and use this in SQL query based on your requirement. Please refer to the below given code 

   <ej:DropDownList runat="server" ID="TradesDropDown" DataTextField="CustomerID" DataValueField="ShipCity" AutoPostBack="true" DataSourceID="SqlData" Width="200px" EnableIncrementalSearch="False" FilterType="Contains" SelectedIndex="0" OnValueSelect="TradesDropDown_ValueSelect"> 

  </ej:DropDownList> 

    <asp:SqlDataSource ID="SqlData" runat="server" ConnectionString="<%$ ConnectionStrings:SQLConnectionString %>" SelectCommand="SELECT * FROM [Orders]"> 

        <SelectParameters> 

    <asp:Parameter Name="ShipCity" Type="String" DefaultValue="Reims" /> 

  </SelectParameters> 

    </asp:SqlDataSource> 

    <ej:Button runat="server" ID="btn" OnClick="btn_Click" Text="Check"></ej:Button> 

Aspx.CS: 

protected void Page_Load(object sender, EventArgs e) 

        { 

            if (!IsPostBack) 

            { 

                SqlConnection myConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["SQLConnectionString"].ToString()); 

                dt = new DataTable("Order"); 

                SqlCommand cmd = new SqlCommand(); 

                cmd.Connection = myConnection; 

                cmd.CommandText = "select * from Orders"; 

                cmd.CommandType = CommandType.Text; 

                SqlDataAdapter da = new SqlDataAdapter(); 

                da.SelectCommand = cmd; 

                if ((myConnection.State == ConnectionState.Closed)) 

                { 

                    myConnection.Open(); 

                } 

 

                da.Fill(dt); 

                Session["SqlDataSource"] = dt; 

            } 

        } 

 

        protected void TradesDropDown_ValueSelect(object sender, Syncfusion.JavaScript.Web.DropdownListEventArgs e) 

        { 

            Session["Selected"] = e.Value; 

        } 

 

        protected void btn_Click(object Sender, Syncfusion.JavaScript.Web.ButtonEventArgs e) 

        { 

            var value = Session["Selected"]; 

        } 

In our sample, we have just assigned the session variable value to a variable on button click. You can use this in SQL query based on your scenario.  Sample can be downloaded from the below link 

http://www.syncfusion.com/downloads/support/forum/144217/ze/DDLSql-212970872 

Please let us know if you require any further assistance. 

Thanks, 

Christo