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i have mail.aspx page. which have to a compose mail facility? also, user can select from user account to user, cc and bccs. along with them when update panel update method calls all previous values from text box getting empty. for avoiding them I create one method that takes previous values and renders with them for a specific condition.

here is my method :

  private void SetViewStateData(bool sTitle, bool sFromuser, bool sTouser, bool sCc, bool sBcc, bool sBody)
        {
            if (sTitle.Equals(true))
            {
                ViewState["sTitle"] = Request.Form.Get("txt_ComName1");
            }
            else
            {
                ViewState["sTitle"] = string.Empty;
            }
            if (sFromuser.Equals(true))
            {
                ViewState["sFromuser"] = Request.Form.Get("txt_ComName2");
            }
            else
            {
                ViewState["sFromuser"] = string.Empty;
            }
            if (sTouser.Equals(true))
            {
                ViewState["sTouser"] = Request.Form.Get("txt_ComName3");
            }
            else
            {
                ViewState["sTouser"] = string.Empty;
            }
            if (sCc.Equals(true))
            {
                ViewState["sCc"] = Request.Form.Get("txt_ComName4");
            }
            else
            {
                ViewState["sCc"] = string.Empty;
            }
            if (sBcc.Equals(true))
            {
                ViewState["sBcc"] = Request.Form.Get("txt_ComName5");
            }
            else
            {
                ViewState["sBcc"] = string.Empty;
            }
            if (sBody.Equals(true))
            {
                ViewState["sBody"] = Request.Form.Get("CKEditor1");
            }
            else
            {
                ViewState["sBody"] = string.Empty;
            }
            txt_ComName1.Text =  sTitle.Equals(false) ? string.Empty : ViewState["sTitle"].ToString();
            txt_ComName2.Text = sFromuser.Equals(false) ? string.Empty : ViewState["sFromuser"].ToString();
            txt_ComName3.Text = sTouser.Equals(false) ? string.Empty : ViewState["sTouser"].ToString();
            txt_ComName4.Text = sCc.Equals(false) ? string.Empty : ViewState["sCc"].ToString();
            txt_ComName5.Text = sBcc.Equals(false) ? string.Empty : ViewState["sBcc"].ToString();
            CKEditor1.Text = sBody.Equals(false) ? string.Empty : ViewState["sBody"].ToString();
        }

this raise error when txt_ComName2.Text sets from view state value if bool status true or string.empty. however, this works fine with a first text box. when second it's given me an error like : 

Server Error in '/EASYMAIL_METRO' Application.   Object reference not set to an instance of an object.    Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 
     Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.     
    Source Error: 
    Line 240:        }
    Line 241:        txt_ComName1.Text =  sTitle.Equals(false) ? string.Empty : ViewState["sTitle"].ToString();
     Line 242:        txt_ComName2.Text = sFromuser.Equals(false) ? string.Empty : ViewState["sFromuser"].ToString();
    Line 243:        txt_ComName3.Text = sTouser.Equals(false) ? string.Empty : ViewState["sTouser"].ToString();
    Line 244:        txt_ComName4.Text = sCc.Equals(false) ? string.Empty : ViewState["sCc"].ToString();        Source File: c:\shalin\EASYMAIL_METRO\mail.aspx.cs    Line: 242     
 Stack Trace:   

 [NullReferenceException: Object reference not set to an instance of an object.]
   mail.SetViewStateData(Boolean sTitle, Boolean sFromuser, Boolean sTouser, Boolean sCc, Boolean sBcc, Boolean sBody) in c:\shalin\EASYMAIL_METRO\mail.aspx.cs:242
   mail.btn_add_Click(Object sender, EventArgs e) in c:\shalin\EASYMAIL_METRO\mail.aspx.cs:1823
   mail.Page_Load(Object sender, EventArgs e) in c:\shalin\EASYMAIL_METRO\mail.aspx.cs:71
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +51
   System.Web.UI.Control.OnLoad(EventArgs e) +95
   System.Web.UI.Control.LoadRecursive() +59
    System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +678

what's going wrong with this...please help me, guys...

SUNIL DHAPPADHULE
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shalin gajjar
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  • As the error suggests, your `Request.Form.Get("txt_ComName2")` is not being set to null. Have you tried debugging your code and investigating if you are getting all the values in your `Request.Form.Get`? – Rahul Sharma May 15 '19 at 09:48
  • well I get null value is there wrong method for getting previous value posted with request.form – shalin gajjar May 15 '19 at 10:29
  • Yes, that would be the case here. If you are getting `null` it means that you are not receiving any value from your `Request.Form` – Rahul Sharma May 15 '19 at 10:30
  • then what should I do?? – shalin gajjar May 15 '19 at 10:32
  • I feel that you are using `Request.Form.Get` incorrectly to get your form values. I would start investigating there. This link might be helpful: https://stackoverflow.com/questions/9956180/get-posted-value-in-c-sharp-asp-net – Rahul Sharma May 15 '19 at 10:40
  • can I get specific values from txt_ComName2 with postedValues – shalin gajjar May 15 '19 at 11:01
  • Instead of reading and saving individual objects in `ViewState` it's easier to define an object which contains all of the values. Load it from `ViewState` in `PreRender` and assign it to a field. If it's not in `ViewState` (first load) create a new instance and assign it to the field. Update the object instead of updating `ViewState`. Then, at the end, save the whole object to `ViewState`. It makes the whole thing a little easier to visualize and manage. – Scott Hannen May 15 '19 at 13:49

0 Answers0