CODEWITHSUNDEEP
c#asp.net
CaptainRabbit
CaptainRabbit

Reputation: 25

Not able to store information while postback after creating dynamic dropdown in ASP.NET

here is my code

after button 2 click event it is creating the dropdown in table rows but when I try to save by button 1 click event it just disappear. I have not find any solution regarding this. I have used find control view State etc but it's not helping.

I want to store selected values of dropdown after button_1 click event starts.

public partial class StudentClassSectionMapping : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if(!IsPostBack)
            {
                ClassCode.Enabled = false;

        }
    }

    protected void Button2_Click(object sender, EventArgs e)
    {
        UpdateModalShowFlag.Value = "true";
        Check.Value = "true";
        CreateTableRows();
    }

    private void CreateTableRows()
    {

        long h = long.Parse(LinkButtonIdCarrier.Value);
        List<StudentsClassSectionMapping.StudentsClassSectionMappingForm> allStudentsInClass = StudentsClassSectionMapping.GetStudentsinClass(h);
        ClassMaster.ClassMasterForm classCode = Schoolclasses.GetInfo(h);
        ClassCode.Text = classCode.cCode;
        List<StudentsClassSectionMapping.StudentsClassSectionMappingForm> allSectionsInClass = StudentsClassSectionMapping.GetSectionsinClass(h);
        foreach (StudentsClassSectionMapping.StudentsClassSectionMappingForm studentList in allStudentsInClass)
        {
            TableRow row = new TableRow();
            TableCell cell1 = new TableCell();
            TableCell cell2 = new TableCell();
            TableCell cell3 = new TableCell();
            DropDownList t = new DropDownList();
            t.Items.Add("No Section");
            foreach (StudentsClassSectionMapping.StudentsClassSectionMappingForm sectionList in allSectionsInClass)
            {
                t.Items.Add(sectionList.ssSection);
                t.Items[t.Items.Count - 1].Value = sectionList.ssSectionID.ToString();
            }
            t.Attributes.Add("class", "form-control");

            t.ID = studentList.ssStudentId.ToString();
            cell1.Text = studentList.ssName;
            cell2.Text = studentList.ssRegistrationNumber;
            cell3.Controls.Add(t);
            row.Cells.Add(cell1);
            row.Cells.Add(cell2);
            row.Cells.Add(cell3);
            Table1.Rows.Add(row);
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        CreateTableRows();
        long h = long.Parse(LinkButtonIdCarrier.Value);
        List<StudentsClassSectionMapping.StudentsClassSectionMappingForm> allStudentsInClass = StudentsClassSectionMapping.GetStudentsinClass(h);
        foreach (StudentsClassSectionMapping.StudentsClassSectionMappingForm studentList in allStudentsInClass)
        {

            DropDownList d = Table1.FindControl(studentList.ssStudentId.ToString()) as DropDownList;
            if (d != null)
            {


                if (d.SelectedIndex != 0)
                {
                    StudentsClassSectionMapping.StudentsClassSectionMappingForm studentSectionMapping = new StudentsClassSectionMapping.StudentsClassSectionMappingForm();
                    studentSectionMapping.ssClassId = h;
                    studentSectionMapping.ssStudentId = studentList.ssStudentId;
                    studentSectionMapping.ssStudentId = long.Parse(d.SelectedItem.Value);
                    StudentsClassSectionMapping.addSectionStudentMapping(studentSectionMapping);
                }
                else 
                {
                    StudentsClassSectionMapping.StudentsClassSectionMappingForm studentSectionMapping = new StudentsClassSectionMapping.StudentsClassSectionMappingForm();
                    studentSectionMapping.ssClassId = h;
                    studentSectionMapping.ssStudentId = 0;
                    studentSectionMapping.ssStudentId = 0;
                    StudentsClassSectionMapping.addSectionStudentMapping(studentSectionMapping);
                }
            }
        }
    }

Upvotes: 1

Views: 29

Answers (1)

Pranay Rana
Pranay Rana

Reputation: 176896

It get vanished/disappear because you added it dynamically on page. If you want it back or want to reserver control which is dynamically created you need to recreate again and need to add dynamically.

Here is good example of how you can do it : How to create controls dynamically in ASP.NET and retrieve values from it

Upvotes: 1

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