How do I solve problem with dropdownlist change event firing once then skips one change event then fires again then skips(alternate change event firing)... And so on ?

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I have a dropdown list inside update panel . it works fine on several machines but on specific machines it works on alternate change events.

Example :

Initially it is set to 0 index "Select Serial No"
When i Choose say SrNo1 , change event doesnt fire
When i choose say SrNo2, change event fires
When i Choose say SrNo3 , change event doesnt fire
When i choose say SrNo4, change event fires
and so on...

Code :

C#

protected void ddlCollection_SelectedIndexChanged(object sender, EventArgs e)
      {

          ddlSerial.SelectedIndex = -1;
          hdfQDSID.Value = "";
          txtQuantity.Text = "";
          lblTypeT.Text = "";
          lblQds.Text = "";
          lnkWHStock.Text = "";
          lblPieces.Text = "";
          lblUnit.Text = "";


          string CollectionID = ddlCollection.SelectedValue.ToString();

          if (ddlCollection.SelectedValue.ToString() != "0")
          {

              DataTable dt = new DataTable();
              DataSet ds = objBAL.getGridCollectionSrNo(CollectionID.ToString());

              if (ds.Tables[1].Rows[0]["COLLECTION_STATUS"].ToString() == "DISCONTINUED")
              {
                  ScriptManager.RegisterStartupScript(Page, GetType(), "CollectionDscontiAler", "<script>alert('This Collection has been discontinued.');</script>", false);
              }


              dt = ds.Tables[0];
              ddlSerial.DataSource = dt;
              ddlSerial.DataTextField = "SR_NO";
              ddlSerial.DataValueField = "SR_NO";
              ddlSerial.DataBind();
              ddlSerial.Items.Insert(0, new System.Web.UI.WebControls.ListItem("Select Sr No", "0"));
              ddlSerial.SelectedIndex = 0;
          }
      }

C#

protected void ddlSerial_SelectedIndexChanged(object sender, EventArgs e)
      {
          hdfQDSID.Value = "";
          txtQuantity.Text = "";
          lblTypeT.Text = "";
          lblQds.Text = "";
          lnkWHStock.Text = "";
          lblPieces.Text = "";
          lblUnit.Text = "";

          string QDSName = string.Empty;
          string QDSID = string.Empty;
          string TypeOfFabric = string.Empty;

          string CollectionID = ddlCollection.SelectedValue.ToString();
          string SrNo = ddlSerial.SelectedValue.ToString();


          if (SrNo != "0" && CollectionID != "0")
          {

              DataTable dt = new DataTable();
              DataSet dsQdsName = objBAL.getGridCollectionQDS(CollectionID, SrNo);  //uspB2BCustomerPortal_uspGetCollectionQDS
              dt = dsQdsName.Tables[0];

              if (dt.Rows.Count > 0)
              {
                  QDSName = dt.Rows[0]["QDSName"].ToString();
                  QDSID = dt.Rows[0]["QDS_ID"].ToString();
                  hdfMultipleOf.Value = dt.Rows[0]["MULTIPLE_OF"].ToString();
                  if (dsQdsName.Tables[1].Rows[0]["PRODUCT_STATUS"].ToString() == "DISCONTINUED")
                  {
                      ScriptManager.RegisterStartupScript(Page, GetType(), "QDSDiscontinuedAlertU", "<script>alert('This QDS has been discontinued.');</script>",true);
                  }

              }

              TypeOfFabric = lblOrderTypeDesription.Text.ToString();
              if (QDSName != "")
              {
                  lblQds.Text = QDSName.ToString();
                  hdfQDSID.Value = QDSID.ToString();

                  //bool result = CheckQDSOrderForCustomer();

                  //if (result)
                  //{


                  if (QDSID != "")
                  {
                      //Code for WHStock & No of Pcs.
                      B2B_Order_Master_SAP_BAL obj_BAL = new B2B_Order_Master_SAP_BAL();
                      DataSet dsWHStockinfo = obj_BAL.getWHStock(QDSID, hfCustomerId.Value.ToString());   //usp_B2BCustomerPortal_getCreateOrderWHStock
                      lnkWHStock.Text = dsWHStockinfo.Tables[0].Rows[0]["WHStock"].ToString();
                      lblPieces.Text = dsWHStockinfo.Tables[0].Rows[0]["No_Of_Pieces"].ToString();

                      //if (dsWHStockinfo.Tables[0].Rows[0]["No_Of_Pieces"].ToString() != "")
                      //{
                      //    lblPieces.ForeColor = System.Drawing.Color.Red;
                      //}
                  }

                  if (TypeOfFabric == "Fabric Order")
                  {
                      lblUnit.Text = "Mtrs.";
                  }
                  else if (TypeOfFabric == "Non-Fabric Order" || TypeOfFabric == "Catalogue Order")
                  {
                      lblUnit.Text = "Pcs";
                  }

                  //}
                  //else
                  //{
                  //    ScriptManager.RegisterStartupScript(Page, GetType(), "Last3DaysTwo2", "<script>AlertUser();</script>", false);
                  //    YesAlertUser.Focus();
                  //}
              }
              else
              {
                  lblQds.Text = "QDS Not Found.";
              }
          }
      }

What I have tried:

My Updatepanel is below :

HTML

<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="server">
           <contenttemplate>
</contenttemplate>
           <triggers>
               <asp:AsyncPostBackTrigger ControlID="btnShowInfo" EventName="Click" />
               <asp:AsyncPostBackTrigger ControlID="btnAddItems" EventName="Click" />
               <asp:AsyncPostBackTrigger ControlID="ddlSerial" EventName="SelectedIndexChanged" />
           </triggers>

       <asp:UpdateProgress ID="updPanelProgress" runat="server" AssociatedUpdatePanelID="UpdatePanel1">
           <progresstemplate>
               <div class="pre-loader"></div>
           </progresstemplate>

-- This dropdownlist is causing problem. It is inside a table

HTML

<table><tbody><tr><td>
<asp:DropDownList ID="ddlSerial" runat="server" onchange="SetScroll();" AutoPostBack="true" OnSelectedIndexChanged="ddlSerial_SelectedIndexChanged">

</td></tr></tbody></table>

Posted 10-Jul-16 21:04pm

Abrar Kazi

Updated 11-Jul-16 3:22am

v4

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Comments

Karthik_Mahalingam 11-Jul-16 4:02am

how you are binding the data?

Abrar Kazi 11-Jul-16 4:40am

there is another dropdownlist whose selected index change is assigning values to this dropdownlist.

Karthik_Mahalingam 11-Jul-16 4:45am

ok, cascading drop down ?
post all relevant code.

Abrar Kazi 11-Jul-16 5:28am

check the updated question

Karthik_Mahalingam 11-Jul-16 6:10am

which one is parent/child

Abrar Kazi 11-Jul-16 6:16am

ddlCollection_SelectedIndexChanged : On this dropdown change ddlSerial is filled .. but the problem is on ddlSerial change event

Abrar Kazi 11-Jul-16 6:17am

Please consider UpdatePanel & IIS .. I think one of these 2 are causing problem .

Karthik_Mahalingam 11-Jul-16 6:24am

on which ddl you have the issue
ddlcollection or ddlserial ?>

Abrar Kazi 11-Jul-16 6:35am

issue is on ddlserial.. ChangeEvent occurs once then it doesnt the 2nd time then it occurs the 3rd time not for 4th and so on

Karthik_Mahalingam 11-Jul-16 6:41am

what do you mean by 2nd 3rd?
post back or just selecting the item from ddl serial ?

Abrar Kazi 11-Jul-16 6:43am

when i select item from ddlserial it postbacks.
2nd n 3rd means example : first time when i select a item it selectedindex change event fires .. again when i select a different item selectedindex change event doesnot fires, again when i select it fires etc .. and so on..

Abrar Kazi 11-Jul-16 6:41am

Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 400

It gives this error in console.

Karthik_Mahalingam 11-Jul-16 7:08am

try in during debug mode

Abrar Kazi 11-Jul-16 7:30am

are dear i told u its working on remote server but after deployment it is giving problem

Karthik_Mahalingam 11-Jul-16 7:57am

ok

Abrar Kazi 11-Jul-16 8:14am

no

Karthik_Mahalingam 11-Jul-16 8:18am

ok use try catch block and throw the error..
from that we can get to know the exact error.

Abrar Kazi 11-Jul-16 8:59am

there is no error in the code

Karthik_Mahalingam 11-Jul-16 8:20am

i hope you are getting the error for "DISCONTINUED" status

Abrar Kazi 11-Jul-16 8:58am

its not an error.. yes when a collection is discontinued it goes into alert statement.. after alert if i change item of ddlserial it doesnt fire change event

Abrar Kazi 11-Jul-16 9:20am

ok karthik i got it:
BEFORE :

ScriptManager.RegisterStartupScript(Page, GetType(), "QDSDiscontinuedAlertU", "<script>alert('This QDS has been discontinued.');</script>", true);

AFTER:
ScriptManager.RegisterStartupScript(UpdatePanel1, UpdatePanel1.GetType(), "QDSDiscontinuedAlertU", "<script>alert('This QDS has been discontinued.');</script>", false);

This worked for me.

Abrar Kazi 11-Jul-16 9:21am

Thank you so much for helping me. :)

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Karthik_Mahalingam · Accepted Answer · 2016-07-11T03:22:00

Solution 1

try this

C#

ScriptManager.RegisterClientScriptBlock(this, GetType(), "CollectionDscontiAler", "<script>alert('This Collection has been discontinued.');</script>", false);

Posted 11-Jul-16 3:22am

Karthik_Mahalingam