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How to call a method only once in the first page load in the master page

I have the following case:
Page1.aspx this page has the master page master.aspx.
I have some code in the master page :
if (!Page.IsPostBack)
{
adjustServiceBar();
}
when i click any button in the Page1.aspxit enters the !Page.IsPostBack and execute the method !!
i want this method in the !Page.IsPostBack) only

One way to do this is to set a session variable and then check that variable to ensure your code will fire only once.
Another way is to set a hidden control on your form and play with its text or value property.
According to each scenario the solution may be very complex such as custom derived masterpages and pages that extend the current events functionality to suit your needs.

I believe it is more consistent to check for IsPostBack in content page. You can move this condition to Page1.aspx and expose adjustServiceBar() method in your master page, so that content pages can call it, like Master.adjustServiceBar().

How to get value of a control in a Masterpage using JQuery?

I have a hidden field control in a MasterPage and I want to get the value of the hidden field control using JQuery in a page that uses the MasterPage.
I have the following javascript which exectues if the hidden field in the page has a value:
if(!$('input[type=hidden]').val().length == 0 ) { }
What javascript would I need to check the value of a hidden field in the MasterPage from the page?

There's no seperation between your page and the master page. Both of those concepts are in your ASP.NET layer and the browser simply recieves one HTML document.
If your masterpage specified a hidden input it'll be on your page like any other hidden input.

If that has the affect you want, it should also work in the masterpage, as there is no difference on the client between a master and a content page.

The master page just gets rendered down with the child page as a single HTML, so you would just access it client-side as normal.
Try rewriting this:
if(!$('input[type=hidden]').val().length == 0 ) { }
as
if ($('input[type=hidden]').val()) {}
which is a simpler conditional for if the hidden field has a value. I'm not sure that the ! combined with the == is doing what you want it to do logically. Either way $('input[type=hidden]').val() is more readable IMO.

Problem With Custom Control on Page Using a MasterPage

I have a content page which has a related master page.
I register a prefix <%# TagPrefix ..... and can load other custom controls at that namespace.
However, one particualar control at the same namespace, when added to the aspx page, breaks it.
The control in question inherits from asp:Panel, has a parameterless constructor, defines a few public accessors, and creates some standard child controls, and nothing much else.
Are there some fundamental restrictions to creating custom asp controls that I am breaking unknowingly?

Add the control back to the page. Delete the designer file for the page: .aspx.designer.cs
Then right click on the page and select Convert to Web Application. This should give you the actual error the page has when attempting to write the control definition to your designer file.
I suspect there is a compilation error in your custom control.

My control was attempting to access Page.Header which was null as the master page had not marked the tag with runat="server".
I guess that is a fundamental restriction that I was looking for...

Web Control added in .master control type not found in child page

I have a Web Site project, and within it I have a user Web Control defined in an ascx file.
The control is added to the Site.Master, and it shows up correctly on the page and everything is fine.
I need to override some of the control's fields on one of the pages that derive from Site.Master.
// In OnLoad:
MyControlName control = (MyControlName) Page.Master.GetBaseMasterPage().FindControl("controlID"));
The issue is that MyControlName doesn't register as a valid Type on the child page. If I add a second instance of the control to the child page directly, the above works as needed, but if the control isn't placed directly on the page, and instead is only defined in the master page, the type is undefined. The control is not in a namespace, and is defined within the project, so I don't know why it is having such an issue location the appropriate type.
If I put a breakpoint in the OnLoad, the type listed for the control is ASP.my_control_name_ascx, but using that does not work either.
Why can't the child class reference the correct type? Can I fix this?
Thanks!

The control does not have global scope over the entire project. It will only be selectable as a type on pages where the control is registered. So you have to register the control on the child page:
<%# Register src="WebUserControl.ascx" tagname="WebUserControl" tagprefix="uc1" %>
You will need to add a register tag like above to the top of your child aspx page.
The other option is you could create an interface for the control which exposes the properties or methods you want to access, and put the interface in app_code or some other globally accessible place, then have the control implement the interface, and cast the control to the interface.

The following code works for me:
DropDownList ddlLanguage = (DropDownList)Page.Master.FindControl("ddlLanguage");

I take it GetBaseMasterPage() is your own method? What happens if you try:
MyControlName control = (MyControlName)Page.Master.FindControl("controlId");
?

Not a direct answer to your question, but you might find the #MasterType directive useful.
If you add a line like
<%# MasterType TypeName="ClientName.SiteName.MasterPages.SiteMaster" %>
to the top of your ASPX page, you should be able to refer to the master page in code without having to cast it. This might make it easier for the code to find your control, perhaps?
You could end up with a line like:
// In Page.OnLoad:
MyControlName control = Page.Master.MyControl;
and then expose a new property in your master page that wraps the FindControl call:
// In Site.master.cs
internal MyControlName MyControl
{
get { this.FindControl("controlID"); }
}
Hope this helps!

How to access .Net element on Master page from a Content page?

Is it possible to access an element on a Master page from the page loaded within the ContentPlaceHolder for the master?
I have a ListView that lists people's names in a navigation area on the Master page. I would like to update the ListView after a person has been added to the table that the ListView is data bound to. The ListView currently does not update it's values until the cache is reloaded. We have found that just re-running the ListView.DataBind() will update a listview's contents. We have not been able to run the ListView.DataBind() on a page that uses the Master page.
Below is a sample of what I wanted to do but a compiler error says
"PeopleListView does not exist in the current context"
GIS.master - Where ListView resides
...<asp:ListView ID="PeopleListView"...
GISInput_People.aspx - Uses GIS.master as it's master page
GISInput_People.aspx.cs
AddNewPerson()
{
// Add person to table
....
// Update Person List
PeopleListView.DataBind();
...
}
What would be the best way to resolve an issue like this in C# .Net?

I believe you could do this by using this.Master.FindControl or something similar, but you probably shouldn't - it requires the content page to know too much about the structure of the master page.
I would suggest another method, such as firing an event in the content area that the master could listen for and re-bind when fired.

Assuming the control is called "PeopleListView" on the master page
ListView peopleListView = (ListView)this.Master.FindControl("PeopleListView");
peopleListView.DataSource = [whatever];
peopleListView.DataBind();
But #palmsey is more correct, especially if your page could have the possibility of more than one master page. Decouple them and use an event.

Option 1 :you can create public property of your master page control
public TextBox PropMasterTextBox1
{
get { return txtMasterBox1; }
set { txtMasterBox1 = value; }
}
access it on content page like
Master.PropMasterTextBox1.Text="SomeString";
Option 2:
on Master page:
public string SetMasterTextBox1Text
{
get { return txtMasterBox1.Text; }
set { txtMasterBox1.Text = value; }
}
on Content Page:
Master.SetMasterTextBox1Text="someText";
option 3 :
you can create some public method that works for you
these approach is not so useful but it helps if you just want to use some limited and predefined control

One think to remember is the following ASP.NET directive.
<%# MasterType attribute="value" [attribute="value"...] %>
MSDN Reference
It will help you when referencing this.Master by creating a strongly typed reference to the master page. You can then reference your ListView without needing to CAST.

you can access with the code this.Master.FindControl(ControlID) which control you wish. It returns the reference of the control, so that the changes are effective. about firing an event could not be possible each situation.

Assuming your master page was named MyMaster:
(Master as MyMaster).PeopleListView.DataBind();
Edit: since PeopleListView will be declared protected by default, you will either need to change this to public, or create a public property wrapper so that you can access it from your page.