Hi,

I wanna ask a question about dropdownlist control in ASP.NET 2.0,

I've a Dropdownlist (d1) and i want add 5 items in dropdownlist on the Page Load through coding.

I want to use Add and AddRange Both methods but i'dt know how to use these both methods, So can anybody give me a code for this,

 

Hi,

you can find information in the documentation of the ListItemCollection members: AddRange. The Items property on the DropDownList is of the type ListItemCollection btw so you can use this class members.

Grz, Kris.

Hope this helps:

DropDownList.Items.Add("First Item")
DropDownList.Items.Add("Second Item")

To add items to the DropDownList, along with a Value Field, you can do something like this (the second item is the one that populates the Value:

ddl2.Items.Add(New ListItem("Item 1", "1"))
ddl2.Items.Add(New ListItem("Item 2", "2"))

Links:
http://aspnet101.com/aspnet101/tutorials.aspx?id=4
http://authors.aspalliance.com/stevesmith/articles/dotnetlistbox2.asp

Hello to ALL

Now i understand the concept behind the Add function of dropdownlist

For add function i'm using this

dd1.Add(new ListItem("Text","Value")

dd1.Add(new ListItem("Text1","Value1")

                  AND

dd1.Add("Text")

dd1.Add("Text1")

 

But i still have a problem with AddRange function of DropDownlist

So can anyone give me a demo code explaining the concept of AddRange methode.

prashant_victory@hotmail.com:

So can anyone give me a demo code explaining the concept of AddRange methode.

Hi,

did you actually take a look at the link I provided in my previous post? It shows with an example how you can create an array of ListItem objects and add this with the AddRange method.

Grz, Kris.

Hello XIII

The link that u've given to me is not about how to adding the item in DropDownList through AddRange Methode.

The link that u have given to me is usefull with List box control, and one more thing that code uses a for loop but if i have only two items and i want to add that items through AddRange methode in DropDownList.

The code u given is fisrt adding the items in the ListItem array and then adding that items to the ListItemCollection but in dropdownlist addrange methode not accept a listitemcollection only accepts the Listitem object.

I'm doing like this but it give me NullRefrence Exception

Dim arr(10) As ListItem     'If u put arr() in Place of arr() or if i put new keyword it giving me probs.

arr(0) =

New ListItem

arr(0).Text =

"A"

arr(0).Value =

"1"

arr(1) =

New ListItem

arr(1).Text =

"B"

arr(1).Value =

"2"

cboSearch.Items.AddRange(arr)

 

OR if u think the code site that u have posted is works with dropdown so please, give me a proper code.

Please its a request.

Byeeeeeeeeeeeee and Take Care.

I think you should do it this way:

Dim arr(2) as ListItem
arr(0) = new ListItem( "A", "1" )
arr(1) = new ListItem( "B", "2" )

cboSearch.Items.AddRange(arr)



Anyway, here's an example extracted from MSDN
Dim MyListItemCollection As ListItemCollection = New ListItemCollection()

' Dimensions an array of ListItems that are used to populate the collection.   
Dim NewListItemArray(TempDataTable.Count - 1) As System.Web.UI.WebControls.ListItem

' Populates the array of ListItems with generic data.
Dim i As Integer
For i = 0 To TempDataTable.Count - 1
    NewListItemArray(i) = New ListItem()
    NewListItemArray(i).Text = "Item " + i.ToString()
    NewListItemArray(i).Value = i.ToString()
Next

' Adds an entire array of ListItem objects to the collection.
MyListItemCollection.AddRange(NewListItemArray)

Well, if you're writing the code the way it should be I have no idea what could be the problem

prashant_victory@hotmail.com:

Hello XIII

The link that u've given to me is not about how to adding the item in DropDownList through AddRange Methode.

The link that u have given to me is usefull with List box control, and one more thing that code uses a for loop but if i have only two items and i want to add that items through AddRange methode in DropDownList.

The code u given is fisrt adding the items in the ListItem array and then adding that items to the ListItemCollection but in dropdownlist addrange methode not accept a listitemcollection only accepts the Listitem object.

I'm doing like this but it give me NullRefrence Exception

Dim arr(10) As ListItem     'If u put arr() in Place of arr() or if i put new keyword it giving me probs.

arr(0) =

New ListItem

arr(0).Text =

"A"

arr(0).Value =

"1"

arr(1) =

New ListItem

arr(1).Text =

"B"

arr(1).Value =

"2"

cboSearch.Items.AddRange(arr)

 

OR if u think the code site that u have posted is works with dropdown so please, give me a proper code.

Hi,

of course it works. Besides that the ListBox and DropDownList controls share the same base class ListControl. The example indeed used a for loop to fill up the array but you can also do that manually.

Take a look at this small code snippet I prepared for you:

1    <%@ Page Language="C#" AutoEventWireup="true" CodeFile="DDLAddRange.aspx.cs" Inherits="DDLAddRange" %>
2    
3    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
4    
5    <html xmlns="http://www.w3.org/1999/xhtml" >
6    <head runat="server">
7        <title>Untitled Page</title>
8    </head>
9    <body>
10       <form id="form1" runat="server">
11       <div>
12           <asp:DropDownList ID="DropDownList1" runat="server">
13           </asp:DropDownList></div>
14       </form>
15   </body>
16   </html>

1    using System;
2    using System.Data;
3    using System.Configuration;
4    using System.Collections;
5    using System.Web;
6    using System.Web.Security;
7    using System.Web.UI;
8    using System.Web.UI.WebControls;
9    using System.Web.UI.WebControls.WebParts;
10   using System.Web.UI.HtmlControls;
11  
12   public partial class DDLAddRange : System.Web.UI.Page
13   {
14       protected void Page_Load(object sender, EventArgs e)
15       {
16  
17           ListItem[] items = new ListItem[3];
18           items[0] = new ListItem("One", "1");
19           items[1] = new ListItem("Two", "2");
20           items[2] = new ListItem("Three", "3");
21  
22           DropDownList1.Items.AddRange(items);
23           DropDownList1.DataBind();
24  
25       }
26   }

 Grz, Kris.

Hello XIII ,

The coding that u have posted is working perfectly in C# But i'm using VB as a language to develop ASP.NET application and the code that u have posted not work in VB

I writing ur code in VB as ,

Dim a As New ListItem(3)

Items(0) =

New ListItem("One", "1")

Items(1) =

New ListItem("Two", "2")

Items(2) =

New ListItem("Three", "3")

cboSearch.Items.AddRange(Items)

cboSearch.DataBind()

This code gives me a problem of  "Unable to cast object of type 'System.Collections.Specialized.HybridDictionary' to type 'System.Web.UI.WebControls.ListItem[]'."

So can u do the same in ASP.NET using vb as a language.

Hi,

you can use a C# to VB.NET convertor.

Grz, Kris.

Dim

items(3) As ListItem

items(0) =

New ListItem("One", "1")

items(1) =

New ListItem("Two", "2")

items(2) =

New ListItem("Three", "3")

cboSearch.Items.AddRange(items)

cboSearch.DataBind()

 

The code that is generated by C# to VB converter is mentioned above But still it giving me the problem of NullRefrence Exception,

So please can u try it once and please solve the problem please,

That's because in VB, arrays are always 1 larger than what is declared in the Dim statement, and the last element is not being initialized.

Try this:

Dim items(2) As ListItem
items(0) = New ListItem("One", "1")
items(1) = New ListItem("Two", "2")
items(2) = New ListItem("Three", "3")
cboSearch.Items.AddRange(items)

cboSearch.DataBind()

Or this:

Dim items As ListItem() = _
{New ListItem("One", "1"), _
 New ListItem("Two", "2"), _
 New ListItem("Three", "3")}
cboSearch.Items.AddRange(items)

cboSearch.DataBind()

NC...

HEY NC01 ,

both the coding works perfectly,

Your point is correct that array starts counting as 0,1,2....

Thanks

Byeeeeeeeee and Take Care