Hi everyone I have problem about dropdown list. I am using dropdown list with datasource. How can I get that value which I selected ?
// I need a if statement here because my programme doesn't know which value of dropdown list selected and I don't know how to use this with datasource.
if(//if I select quiz 1 from dropdown list ,quiz 1 should list questions.)
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["RegConnectionString"].ConnectionString);
string chooce = "Select Quiz from tblQuiz where Quiz=1 ";
SqlCommand userExist = new SqlCommand(chooce, con);
con.Open();
int temp = Convert.ToInt32(userExist.ExecuteScalar().ToString());
if (temp == 1)
{
if (rbList.Items[0].Selected == true)
{
string cmdStr = "Select Question from tblQuiz where ID=1";
SqlCommand quest = new SqlCommand(cmdStr, con);
lblque.Text = quest.ExecuteScalar().ToString();
con.Close();
}
You can bind the DropDownList in different ways by using List, Dictionary, Enum, DataSet DataTable.
Main you have to consider three thing while binding the datasource of a dropdown.
you can use following code to bind a dropdownlist to a datasource as a datatable:
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnString"].ConnectionString);
SqlCommand cmd = new SqlCommand("Select * from tblQuiz", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt=new DataTable();
da.Fill(dt);
DropDownList1.DataTextField = "QUIZ_Name";
DropDownList1.DataValueField = "QUIZ_ID"
DropDownList1.DataSource = dt;
DropDownList1.DataBind();
if you want to process on selection of dropdownlist, then you have to change AutoPostBack="true" you can use SelectedIndexChanged event to write your code.
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
string strQUIZ_ID=DropDownList1.SelectedValue;
string strQUIZ_Name=DropDownList1.SelectedItem.Text;
// Your code..............
}
It depends on how you set the defaults for the dropdown. Use selected value, but you have to set the selected value. For instance, I populate the datasource with the name and id field for the table/list. I set the selected value to the id field and the display to the name. When I select, I get the id field. I use this to search a relational table and find an entity/record.
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
drpCategory.DataSource = CategoryHelper.Categories;
drpCategory.DataTextField = "Name";
drpCategory.DataValueField = "Id";
drpCategory.DataBind();
}
}
Refer to example at this link. It may be help to you.
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.dropdownlist.aspx
void Page_Load(Object sender, EventArgs e)
{
// Load data for the DropDownList control only once, when the
// page is first loaded.
if(!IsPostBack)
{
// Specify the data source and field names for the Text
// and Value properties of the items (ListItem objects)
// in the DropDownList control.
ColorList.DataSource = CreateDataSource();
ColorList.DataTextField = "ColorTextField";
ColorList.DataValueField = "ColorValueField";
// Bind the data to the control.
ColorList.DataBind();
// Set the default selected item, if desired.
ColorList.SelectedIndex = 0;
}
}
void Selection_Change(Object sender, EventArgs e)
{
// Set the background color for days in the Calendar control
// based on the value selected by the user from the
// DropDownList control.
Calendar1.DayStyle.BackColor =
System.Drawing.Color.FromName(ColorList.SelectedItem.Value);
}
Source: Stackoverflow.com