Ribbon Customization in SharePoint 2013

Question

Hello Friends,
i want to customize ribbon . i written bellow custom action
<CustomAction Id="WebPartContextualTabs" Location="CommandUI.Ribbon">
    <CommandUIExtension>
      <CommandUIDefinitions>
        <CommandUIDefinition Location="Ribbon.ContextualTabs._children">
          <ContextualGroup Id="WebPartContextualTabGroup" ContextualGroupId="WebPartContextualTab" Sequence="150" Title="WebPart Contextual Tab Tools" Color="Green"
Command="WebPartContextualTab.OnEnableContextualTab">
            <Tab Id="Ribbon.PropertyChangerTab"
                 Title="Tools"
                 Sequence="501">
             <Scaling Id="Ribbon.PropertyChangerTab.Scaling">
                <MaxSize Id="Ribbon.PropertyChangerTab.MaxSize"
                   GroupId="Ribbon.PropertyChangerTab.PropertyGroup"
                   Size="LargeLarge" />
             </Scaling>
              <Groups Id="Ribbon.PropertyChangerTab.Groups">
                <Group Id="Ribbon.PropertyChangerTab.PropertyGroup" Title="PropertyGroup" Sequence="25"
                 Template="Ribbon.Templates.Flexible2" >
                  <Controls Id="Ribbon.PropertyChangerTab.PropertyGroup.Controls">
                    <Button Id="Ribbon.PropertyChangerTab.PropertyGroup.GeneralDialogButton"
                            LabelText="Write to Web Part"
                            Command="WebPartContextualTabs.OnPostback"
                            TemplateAlias="o1"
                            Sequence="15"
                            Image16by16="/_layouts/Images/TestProject/16x16Placeholder.png"
                            Image32by32="/_layouts/Images/TestProject/32x32Placeholder.png" />
                  </Controls>
                </Group>
              </Groups>
            </Tab>
          </ContextualGroup>
        </CommandUIDefinition>
      </CommandUIDefinitions>
      <CommandUIHandlers>
        <CommandUIHandler Command="WebPartContextualTab.OnEnableContextualTab" CommandAction=""></CommandUIHandler>
        <CommandUIHandler Command="WebPartContextualTab.OnPostback" CommandAction="javascript:_doPostBack('RibbonizedWebPartPostback','');"/>
      </CommandUIHandlers>
    </CommandUIExtension>
  </CustomAction>
ok i have create a contextual group, A tab and a button which does postback, the ribbon shows in Webpart whose cs code is shown bellow.
        public string POSTBACK_EVENT = "RibbonizedWebPartPostback";
        protected override void CreateChildControls()
            this.Controls.Add(new LiteralControl("<em>Ribbonised Webpart test</em>"));
            RaisePostBack();
        private void RaisePostBack()
            if (this.Page.Request["_EVENTTARGET"] == POSTBACK_EVENT)
                this.Controls.Add(new LiteralControl("<em>This is from postback</em>"));
        protected override void OnPreRender(EventArgs e)
            base.OnPreRender(e);
            LoadAndActivateContextualTab();
        private void LoadAndActivateContextualTab()
            SPRibbon ribbon = SPRibbon.GetCurrent(this.Page);
            if (ribbon != null)
                ScriptLink.RegisterScriptAfterUI(this.Page, "SP.Ribbon.Js", false, true);
                ribbon.MakeContextualGroupInitiallyVisible("Ribbon.WebPartContextualTabGroup", string.Empty);
                ribbon.MakeTabAvailable("Ribbon.PropertyChangerTab");
i am facing two probulems.
1. when webpartpage is loaded tab is not visible. how ever when i click on some other ribbon tabs such as page it is showing
2. when i click on the button then _EVENTTARGET is null.
Please guide me or at least suggest some link from where i can build strong conceps???
Thanks
Mukesh

Answer 1

Hello all
in spite of _EVENTTARGET is null if i pass _EVENTARGUMENT then i can retrive that argument .
can not understand whats happening.
Please Help.
Mukesh