mercredi 25 février 2009

Dynamically creat a SPView with checkbox that will be display in a dynamically created ListViewe

Hi,

My problem was this one :

"I need to display on a specific page the default view of a list, BUT beside each items of this list must be displayed a checkbox in order to be able to select items on this list"
huuu....
The solution I chose was to recreate a clone of the defaultview that will never be displayed to the users but that will be selected as SPView of the ListView I create on my page.
Here we go...

1/ My Page takes in parameter the ID of the list I'm working on, i call the parameter "List":
Guid ListId = new Guid(this.Page.Request["List"]);
2/ Then whenever I reach the page, i check whether the view already exists, if not i create it cloning the default view and adding to it a checbox field. If the clone of the actual defaultview exists i just use it! Easy! In my code below, the listview object is called Select_List




bool creatingView = false;
SPView newView = null;
SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite Mysite = new SPSite(siteID))
{
SPWeb MyWeb = Mysite.OpenWeb(webID);
MyWeb.AllowUnsafeUpdates = true;
SPList MyList = MyWeb.Lists[ListId];
foreach (SPView view in MyList.Views)
{
if (view.Title.Equals(MyList.DefaultView.Title+ "_CloneForSelect"))
{
newView = view;
}
}
if (newView == null)
{
if (!MyList.Fields.ContainsField("Select"))
{
MyList.Fields.AddFieldAsXml("<Field Type=\"Computed\" ReadOnly=\"TRUE\" Name=\"ListItemSelection\" DisplayName=\"Select\" Sortable=\"FALSE\" Filterable=\"FALSE\" EnableLookup=\"FALSE\" SourceID=\"http://schemas.microsoft.com/sharepoint/v3\" StaticName=\"ListItemSelection\">" +"<FieldRefs> <FieldRef Name=\"ID\" /> </FieldRefs>" + "<DisplayPattern> <HTML><![CDATA[<input id=\"chk_select]]></HTML><Column Name=\"ID\" HTMLEncode=\"TRUE\" /><HTML><![CDATA[\" name=\"chk_select\" type=\"checkbox\" ]]></HTML>" + "<HTML><![CDATA[LItemId=\"]]></HTML>" + "<Column Name=\"ID\" HTMLEncode=\"TRUE\" />" + "<HTML><![CDATA[\"/> ]]></HTML>" + "</DisplayPattern></Field>");
}
SPFieldComputed fieldComp = (SPFieldComputed)MyList.Fields["Select"];
newView = MyList.DefaultView.Clone(MyList.DefaultView.Title + "_CloneForSelect", 1000, true, false);
newView.Hidden = true;
newView.Scope = SPViewScope.FilesOnly;
newView.ViewFields.Add(fieldComp);
newView.Update();
creatingView = true;
}
MyWeb.Dispose();
}
});
if (!creatingView)
{
Select_List.ViewId = newView.ID.ToString();
}
else
{
Response.Write("");
}
Select_List.ListId = this.Page.Request["List"];
Now, let me explain the code a little bit.

1/ How to create a column Checkbox in a list?

It's quite tricky cause you must create the column using a CAML definition.


 if (!MyList.Fields.ContainsField("Select"))
{
MyList.Fields.AddFieldAsXml("<Field Type=\"Computed\" ReadOnly=\"TRUE\" Name=\"ListItemSelection\" DisplayName=\"Select\" Sortable=\"FALSE\" Filterable=\"FALSE\" EnableLookup=\"FALSE\" SourceID=\"http://schemas.microsoft.com/sharepoint/v3\" StaticName=\"ListItemSelection\">" +"<FieldRefs> <FieldRef Name=\"ID\" /> </FieldRefs>" +
"<DisplayPattern> <HTML><![CDATA[<input id=\"chk_select]]></HTML><Column Name=\"ID\" HTMLEncode=\"TRUE\" /><HTML><![CDATA[\"
name=\"chk_select\" type=\"checkbox\" ]]></HTML>"
+
"<HTML><![CDATA[LItemId=\"]]></HTML>" +
"<Column Name=\"ID\" HTMLEncode=\"TRUE\" />" +
"<HTML><![CDATA[\"/> ]]></HTML>" + "</DisplayPattern></Field>");
}
Sorry for the "+" but it's for my code lisibility! In fact you just create a field where the display is an HTML input component !!
2/ OK, but now, i have the display How do I get my checkboxes values after postback ?
Well, let's continue to be tricky!! I just create two Hidden field on my page

<asp:HiddenField runat="server" id="listSrv_items" />
<asp:HiddenField runat="server" id="checked_ids" />
And on my validation button i fill it before validation using a JS function called fill_ids


<asp:Button ID="Btn_valid" OnClientClick="fill_ids();" OnClick="Btn_valid_Click" runat="server"/>
The js function simply puts inside the listSrv_Items the ids of each item in the list, and checked_ids will finally contain the list of items ids that are checked.

here we go for the js that i manually add to the page in the render method:


protected override void Render(HtmlTextWriter writer)
{
this.ClientScript.RegisterClientScriptBlock(this.GetType(), "MyScript", @"
<script>
function fill_ids()
{
var items= document.getElementById('"
+ listSrv_items.ClientID + @"').value;
var checkedIds= document.getElementById('"
+ checked_ids.ClientID + @"');
checkedIds.value='';
var SParray = items.split(';');
for (ix=0; ix< SParray.length-1; ix++)
{
var item = document.getElementById("
"chk_select""+SParray[ix])
if (item!=null && item.checked)
{
checkedIds.value += SParray[ix] + ';';
}
}
if (checkedIds.value.length>0)
checkedIds.value = checkedIds.value.substr(0,checkedIds.value.length-1);
}
</script>"
);
listSrv_items.Value = "";
foreach (SPListItem item in _rootList.Items)
{
listSrv_items.Value += item.ID + ";";
}
}
Now my field checked_Ids will contain the ids of my checked items so in my Btn_valid_Click; i just have to use it to do anything I want! That's it!

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