将值分配给javascript中的隐藏字段

Question

I am trying to do what seems to be simple but am unable to accomplish

I am trying to set the value of a column after a row focus change in a grid to a hidden value in java script.

My imbedded javascript code:

function OnGridFocusedRowChanged() {
   grdA.GetRowValues(grdA.GetFocusedRowIndex(), 'ClientID', OnGetRowValues);
}

function OnGetRowValues(values) {
  //Set hidden value
  document.getElementById('<%=hdnClientID.ClientID%>').value = values[0];

  //Fire button click
  btnPopulateGrids_Click();        
}

where hdnClientID is the name of my hidden field

In GridA I have the setting as such that OnGridFocusedRowChanged gets executed each time a row focus change takes place.

To this point, it works fine, the values[0] in OnGetRowValues() contains the correct value from the corresponding row in GridA.

But in the corresponding code behind, I cannot access the value from hidden field hdnClientID . Always comes up null when accessing

Current_Client_ID = CInt(hdnClientID.Value);

cannot access or convert any value from hdnClientID.ClientID.

either.

I'm missing something simple.

Answer 1

I had to complete a similar task recently and I too was unable to access the value from codebehind. I researched and found out that it is not that simple and that you can't do it with javascript. What I would recommend is to check if you have jQuery installed and if you do, change your function to this:

function OnGetRowValues(values) {
  //Set hidden value
  $('#<%=hdnClientID.ClientID%>').val(values[0]);

  //Fire button click
  btnPopulateGrids_Click();

  //If you change your HiddenField to have OnValueChange event, you can trigger it with this
  //__doPostBack('<%= CompanyCode.ClientID %>', '');        
}

Also, I guess you are firing some function from code behind with btnPopulateGrids_Click(); . I would recommend adding OnValueChanged="hdnClientID_OnValueChanged"/> to your <asp:HiddenField/> and using my supplied function triggering method.