[CLOSED] MultiSelect indexof listitem always null

**gs_user** · Jul 10, 2012, 2:57 PM

Hi,
When button click, to find the index of multiselect
It's alway return null(-1).
How to resolve it??

<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
    protected void getitem(object sender, DirectEventArgs e)
    {
        Ext.Net.ListItem subitem = new Ext.Net.ListItem();
        subitem.Text = "item1";
        if (MultiSelect1.Items.IndexOf(subitem) > -1)
            Label1.Text = " indexif:" + MultiSelect1.Items.IndexOf(subitem).ToString();
        else
            Label1.Text = " indexif:-1";
          
    }
</script>




<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <ext:ResourceManager ID="ResourceManager1" runat="server">
        </ext:ResourceManager>
        <ext:MultiSelect ID="MultiSelect1" runat="server">
           <Items>
              <ext:ListItem Text="item1">
              </ext:ListItem>
              <ext:ListItem Text="item2">
              </ext:ListItem>
              <ext:ListItem Text="item3">
              </ext:ListItem>
              <ext:ListItem Text="item4">
              </ext:ListItem>
           </Items>
        </ext:MultiSelect>
        <ext:Button ID="Button1" runat="server" Text="get item">
           <DirectEvents>
              <Click OnEvent="getitem"></Click>
           </DirectEvents>
        </ext:Button>
        <ext:Label ID="Label1" runat="server">
        </ext:Label>
    </div>
    </form>
</body>
</html>

**Daniil** · Jul 10, 2012, 5:39 PM

Hi,

To get it working the Comparer should be overrode.

We would suggest you to use lambda expressions to achieve the requirement.

**gs_user** · Jul 11, 2012, 1:47 AM

Please provide examples,thanks again.

Originally Posted by Daniil

Hi,

To get it working the Comparer should be overrode.

We would suggest you to use lambda expressions to achieve the requirement.

**Daniil** · Jul 11, 2012, 10:05 AM

Example

<%@ Page Language="C#" %>

<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>

<script runat="server">
    protected void GetItem(object sender, DirectEventArgs e)
    {
        Ext.Net.ListItem subItem = this.MultiSelect1.Items.First<Ext.Net.ListItem>(item => item.Text == "item1");

        if (subItem != null)
        {
            this.Label1.Text = "found: " + subItem.Text;
        }
        else
        {
            this.Label1.Text = "not found";
        }
    }
</script>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Ext.NET v2 Example</title>
</head>
<body>
    <form runat="server">
        <ext:ResourceManager runat="server" />

        <ext:MultiSelect ID="MultiSelect1" runat="server">
            <Items>
                <ext:ListItem Text="item1" />
                <ext:ListItem Text="item2" />
            </Items>
        </ext:MultiSelect>

        <ext:Button runat="server" Text="Get item" OnDirectClick="GetItem" />

        <ext:Label ID="Label1" runat="server" />
    </form>
</body>
</html>

**gs_user** · Jul 12, 2012, 10:37 AM

Hi

I add listitem in MultiSelect codebehind,The multiselect show listitem work well.
but when click other button to get Items.count,the multiselect has listitems,but count return 0?????

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Web" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

   protected void getcount(object sender, DirectEventArgs e)
    {

        for (int i = 1; i < 4; i++)
        {
            Ext.Net.ListItem subitem = new Ext.Net.ListItem();
            subitem.Text = "item"+i.ToString();
            MultiSelect1.Items.Add(subitem);
        }
        MultiSelect1.Render();
        
    }
    protected void getcount1(object sender, DirectEventArgs e)
    {

        Label1.Text = "count:" + MultiSelect1.Items.Count.ToString();
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <ext:ResourceManager ID="ResourceManager1" runat="server">
        </ext:ResourceManager>
        <ext:MultiSelect ID="MultiSelect1" runat="server" FieldLabel="" DragGroup="grp2"
            DropGroup="grp2">
            <Items>
            </Items>
        </ext:MultiSelect>
        <ext:Button ID="Button1" runat="server" Text="1.Click  to set MutltiSelect">
            <DirectEvents>
                <Click OnEvent="getcount">
                </Click>
            </DirectEvents>
        </ext:Button>
        <ext:Label ID="Label1" runat="server">
        </ext:Label>
        <ext:Button ID="Button2" runat="server" Text="2.Click to get MultiSelect counts">
            <DirectEvents>
                <Click OnEvent="getcount1">
                </Click>
            </DirectEvents>
        </ext:Button>
    </div>
    </form>
</body>
</html>

**Daniil** · Jul 12, 2012, 12:26 PM

If you create something within the DirectEvent/DirectMethod, it won't be recreated automatically during another request.

If you need to use Items during another request, you should recreate them manually.

If you could clarify the initial requirement, we would try to suggest something better/easier.

**gs_user** · Jul 13, 2012, 2:09 AM

I finally understand why every time I add listitems must use the render to refresh screen.
I don't know how to recreate them manually.
My requirment is provide three checkbox to users, when user checked, checkbox value add to multiselect
User can change sequence from multiselect
I have to save multiselect item to database. I use for loop to get multiselect item.
for loop can not work becasue items.count always zero.

<%@ Page Language="C#" %>

<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void setMultiSelect(object sender, DirectEventArgs e)
    {
        if (Ck1.Checked == true)
        {
            Ext.Net.ListItem subitem = new Ext.Net.ListItem();
            subitem.Text = "item1" ;
            MultiSelect1.Items.Add(subitem);          
        }

        if (Ck2.Checked == true)
        {
            Ext.Net.ListItem subitem = new Ext.Net.ListItem();
            subitem.Text = "item2" ;
            MultiSelect1.Items.Add(subitem);
        }

        if (Ck3.Checked == true)
        {
            Ext.Net.ListItem subitem = new Ext.Net.ListItem();
            subitem.Text = "item3" ;
            MultiSelect1.Items.Add(subitem);
        }
        
        MultiSelect1.Render();
        //I add checkbox to multiselect,user can change sequence in multiselect 
        
        
    }
    protected void SaveData(object sender, DirectEventArgs e)
    {
        //I have to get the multiSelect items, but items.counts always 0
        for (int i = 0; i < MultiSelect1.Items.Count; i++)
        {
           // save data to db
            
        }
        
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <ext:ResourceManager ID="ResourceManager1" runat="server">
        </ext:ResourceManager>
        <ext:Checkbox ID="Ck1" runat="server" FieldLabel="ITEM1">
           <DirectEvents>
              <Change OnEvent="setMultiSelect"></Change>
           </DirectEvents>
        </ext:Checkbox>
        <ext:Checkbox ID="Ck2" runat="server" FieldLabel="ITEM2">
            <DirectEvents>
                <Change OnEvent="setMultiSelect">
                </Change>
            </DirectEvents>
        </ext:Checkbox>
        <ext:Checkbox ID="Ck3" runat="server" FieldLabel="ITEM3">
            <DirectEvents>
                <Change OnEvent="setMultiSelect">
                </Change>
            </DirectEvents>
        </ext:Checkbox>
     
        <ext:MultiSelect ID="MultiSelect1" runat="server" FieldLabel="" DragGroup="grp2" DropGroup="grp2">
            <Items>
            </Items>
        </ext:MultiSelect>
        <ext:Button ID="Button1" runat="server" Text="Save Data">
            <DirectEvents>
                <Click OnEvent="SaveData">
                </Click>
            </DirectEvents>
        </ext:Button>
    </div>
    </form>
</body>
</html>

**Daniil** · Jul 13, 2012, 7:34 AM

Thanks for the clarification. But the answer is still the same:

Originally Posted by Daniil

If you create something within the DirectEvent/DirectMethod, it won't be recreated automatically during another request.

If you need to use Items during another request, you should recreate them manually.

You should recreate these Items or send them from client side as a extra parameter of the DirectEvent.

Here is the example how to submit MultiSelect values.
https://examples2.ext.net/#/Form/Mul...t/Submit_Data/

**gs_user** · Jul 13, 2012, 7:53 AM

I actually did not think to use ExtraParams.
that's a good idea for me.
thanks again,again,again

Originally Posted by Daniil

Thanks for the clarification. But the answer is still the same:

You should recreate these Items or send them from client side as a extra parameter of the DirectEvent.

Here is the example how to submit MultiSelect values.
https://examples2.ext.net/#/Form/Mul...t/Submit_Data/

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