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c# - asp.net Keep selected value on dynamically populated / created radiobuttonlist

问题描述:

I hope this question hasn't been asked before in this manner, if it has, I sadly can't find it!

I'm currently trying to create a User Control in which I want a client to select a questionnaire from a dropdownmenu which is dynamically populated on page_load like this:

 DiscoverConnectData(); //gets the items from a database

var formItems = 0;

using (var osContext = new OrganizationServiceContext(_crmAccessor.OrganisationService))

{

var forms = (from f in osContext.CreateQuery("form") select f);

foreach (var form in forms)

{

var name = formulier.GetAttributeValue<string>("name");

var formId = formulier.GetAttributeValue<Guid>("formid");

DropDownList_RP.Items.Insert(formItems, new ListItem(naam, formId.ToString()));

formItems++;

}

}

I've also tried putting the above code inside an if (!Page.IsPostBack), however this didn't fix my problem... Okay, moving on. When the client has selected a questionnaire and hit a button, I have a piece of code that runs through all the questions and answers related to that specific questionnaire in a for each loop and creates Labels and RadioButtonLists for each question. First it loads the questions and answers related to the selected formId:

 var curQuestionName = string.Empty;

var lblId = 0;

_formGuid = new Guid(DropDownList_RP.SelectedValue);

DiscoverConnectData();

using (var osContext = new OrganizationServiceContext(_crmAccessor.OrganisationService))

{

_answerList =

(from a in osContext.CreateQuery("answer")

join v in osContext.CreateQuery("question")

on a["question"] equals v["questionid"]

where ((EntityReference)v["form"]).Id == _formGuid

select new AnswerClass

{

AnswerQuestionId = v.GetAttributeValue<Guid>("questionid"),

QuestionName = v.GetAttributeValue<string>("name"),

Name = a.GetAttributeValue<string>("ansname"),

Score = a.GetAttributeValue<int>("score")

}).ToList();

}

After picking up this data and adding it to a list, I create the Questionnaire items:

 foreach (var ant in _answerList)

{

if (ant.QuestionName != curQuestionName)

{

var vLabel = new Label();

var qid = "Q" + lblId;

vLabel.ID = qid;

vLabel.Text = ant.QuestionName;

Questionnaire.Controls.Add(vLabel);

_aRadioList = new RadioButtonList();

var rblId = "list" + lblId;

_aRadioList.ID = rblId;

Questionnaire.Controls.Add(_aRadioList);

Questionnaire.Controls.Add(new LiteralControl("<br />"));

curQuestionName = ant.QuestionName;

lblId++;

}

_aRadioList.Items.Add(new ListItem((" " + ant.Name), ant.Score.ToString()));

}

This all works fine and I'm getting a list with questions and answers neatly put underneath each other. So far so good!

However, the big problem I'm having is the losing of data on page postback. Whenever the user selects certain answers and I then want to show them a score, or do anything else - the page reloads and all my dynamically added controls are lost. Now I have fixed that issue by putting the relevant functionality above into a function and calling that again when I press the button to show a score, and this recreates the questions and answers, but I lose all the selectedvalues. I don't specifically even need to keep the controls on the page or anything, I just need to keep the selectedvalues in order to do stuff with them!

I can't create the controls on page_load or page_init because I need user input to know exactly which questionnaire to pull from the database. I can't use "hard-coded" values for the dropdownlist items either, because that's not the functionality we're aiming for. We need to pull it all from the database - which I can't access directly, I need to use the DiscoverConnectData() function.

Please, if anyone has any ideas in order to get the functionality I want (also if it means exploring a whole new 'avenue'), please let me know!

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