I have an event in the Master page that I want to access in the pages that use that master page but it doesn't seem to be working.
In the Master
public delegate void NotifyRequest(object sender, EventArgs e);
public class MyMaster
{
public event NotifyRequest NewRequest;
protected void uiBtnNewTask_Click(object sender, EventArgs e)
{
if(NewRequest!= null)
NewRequest(this, e)
}
}
Inherited Page
MyMaster mm = new MyyMaster();
mm.NewRequest += new NotifyRequest(mm_NotifyRequest);
void mm_NotifyRequest(object sender, EventArgs e)
{
Label1.Text = "Wow";
this.Label1.Visible = true;
}
My problem is the event is always null. Any ideas?
You probably need to use the following syntax to access your event in the Master Page
((MyMaster)Master).NewRequest += new NotifyRequest(mm_NotifyRequest);
If you wish to access members of a master page you need to use the page Master attribute and cast it to your master page.
Alternately
If you wish do not wish to use a cast you can use the #MasterType directive to create a strong reference to your master page, in this case MyMaster. So you would be able to access your event like so: Master.NewRequest.
More Reading about Master Pages
Related
Iam tried to hide a div which is placed in master page,but i got an error like this "Object reference not set to an instance of an object".
My codes
<div runat="server" id="cnms">
Cinemas
</div>
public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
AdminMaster admns = new AdminMaster();//This si my admin page
admns.FindControl("cnms").Visible = false;//I got error here
}
}
What went wrong for me?any solution?
The approach you are using is instantiating a new instance of the masterpage, which when you do that it all of the control references are null. You need to use the existing master page instance, using the Page.Master property like the following:
protected void Page_Load(object sender, EventArgs e)
{
AdminMaster admns = (AdminMaster)Page.Master; //This si my admin page
admns.FindControl("cnms").Visible = false;//I got error here
}
I use an ascx user control for manage CRUD o database entity. I reuse this userc control in my aspx page for show in readonly mode the database data of a record on database. The user control have inside a simple FormView and an objectdatasource.
Now, in a aspx page that contains that ascx i have to know, in DATABIND time of the aspx some data of the record of the database that is considerate by the user control. User control are databind after the aspx page, and for this reason i don't have the data. I have to do a select in aspx page on database and after the user control do the same select.
How can i do for optimize this process?
ASCX base events may be fired after your ASPX's base events, but in the whole lifecycle, you can fire your own events.
You could define an Event on your ASCX, make your page register to this event, and then propagate your custom event from your ASCX to your ASPX, with whatever data you need in the arguments
rough example (may not compile) : in the ASCX
public partial YourControl : System.Web.UI.UserControl {
public event EventHandler MyControlDataBound;
public void FireMyControlDataBound()
{
if (MyControlDataBound!= null)
{
MyControlDataBound(this, new EventArgs());
}
}
protected void MyDataBound(object sender, EventArgs e) {
// ......
FireMyControlDataBound();
}
}
and in the ASPX
public partial class MyPage: Page
{
protected void Page_Load(object sender, EventArgs e)
{
yourUserControlInstance.MyControlDataBound += HandleYourDataInYourPage;
}
protected void HandleYourDataInYourPage(object sender, EventArgs e) {
// .. do whatever needed in your page, with your data
// if you have defined a custom Args class that inherits EventArgs, your could collect data here...
}
}
Feel free to create a class that inherits EventArgs to pass data with your event if you need this
You can pass your arguments to your UserContol in init event of your Page
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
var control = (UserControl)this.FindControl("UserControlId");
control.Property = ...;//Pass User Control properties
}
I created a textbox and a submit button in header(User Control) included in a master page
and I want to use that textbox value after clicking submit in my .aspx.vb page.
How can i access that, as the vb page is loaded first and then master page is loading ?
TextBox Val = (TextBox)this.Master.FindControl("TextBoxID");
The best way to communicate from UserControl to Page/MasterPage is using events
The best way to communicate from MasterPage to Page is using events
On this way you don't hardlink UserControls with their Pages/MasterPages and the Page with it's Master.
Add an event to your UserControl that is raised when the user clicks the button, for example:
In UserControl of type MyControl:
public delegate void SubmittedHandler(MyControl ctrl);
public event SubmittedHandler Submitted;
protected void BtnCLick(object sender, EventArgs e) {
Submitted(this);
}
Then add an handler to this event in your MasterPage, handle it and raise the Master's event again:
In Master's codebehind:
public delegate void MyControlSubmittedHandler(MyControl ctrl);
public event MyControlSubmittedHandler ControlSubmitted;
protected void Page_Init(Object sender, EventArgs e) {
this.MyControl1.Submitted += MyControlSubmitted;
}
protected void MyControlSubmitted(MyControl sender) {
ControlSubmitted(sender);
}
Then add an handler to this event to your page:
In your Page:
protected void Page_Init(object sender, EventArgs e) {
((SiteMaster)Master).ControlSubmitted += MasterControlSubmitted;
}
protected void MasterControlSubmitted(MyControl sender){
// do whatever you need to do
}
If you only need to access the TextBox from the page and you don't need to handle the click-event, you could also use properties to achieve this:
add a public property f.e. MyControlText in your UserControl that get/set the TextBox.Text property
add a public property f.e. MyControlText in your Master that get/set your UserControl's MyControlText property
Now you can get/set this property from your page in this way:
((SiteMaster)Master).MyControlText = "Hello World";
I have a .aspx web page, with a html form within it, this also has two input boxes.
Whats the best way to take the input box data and pass it to a new .aspx page where it is dealt with by the request method.
Assuming that the data is not sensitive then the best method to pass it to your new page using Response.Redirect and the querystring using:
protected void MyFormSubmitButton_Click(Object sender, EventArgs e)
{
string value1 = txtValue1.Text;
string value2 = txtValue2.Text;
// create a querystring
string queryString = "x=" + value1 + "&y=" + value2;
// redirect to the encoded querystring
Response.Redirect("NewPage.aspx?" + Server.URLEncode(queryString));
}
This web page has a lot of information which you can use for passing the values from page to page.
http://msdn.microsoft.com/en-us/library/6c3yckfw.aspx#Y1100
Try Server.Transfer:
Terminates execution of the current
page and starts execution of a new
page by using the specified URL path
of the page. Specifies whether to
clear the QueryString and Form
collections.
If you set the preserveForm parameter
to true, the target page will be able
to access the view state of the
previous page by using the
PreviousPage property.
Your main page:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
// ThreadAbortException occurs here.
// See http://support.microsoft.com/kb/312629 for more details.
Server.Transfer("AnotherPage.aspx", true);
}
}
"AnotherPage.aspx":
protected void Page_Load(object sender, EventArgs e)
{
if (PreviousPage != null)
{
// Accessing previous page's controls
}
}
I have hard time to modify a page that had a Custom User Control directly to the ASPX page and now require to have it dynamically loaded when needed only. The User Control does have html and other controls via the ASCX file and has code in the code-behind.
I have read multiple page and have found that I cannot instantiate directly the User Control but should use the Page.LoadControl(...). The problem is not the compiling but when the page load the control it happen that all controls inside the ASCX are null and then crash.
How can I use a User Control that has code in the ASCX and in the code-behind dynamically?
Edit:
Example of what I am doing in (PageLoad or PagePreRender or PagePreInit)
Control c = LoadControl(typeof(MyControl), null);
myControl= (MyControl)c;
myControl.ID = "123";
myControl.Visible = false;
Controls.Add(myControl);
MyControl does have for example <div id="whatever" runat="server">... and inside the MyControl it set the visibility to True or False... but when it does that, now it crash because the "whatever" div is NULL.
What I have done is use the Page.LoadControl method in the Page_Init to add the custom user control to a place holder on the page.
protected void Page_Init(object sender, EventArgs e)
{
//MyControl is the Custom User Control with a code behind file
MyControl myControl = (MyControl)Page.LoadControl("~/MyControl.ascx");
//UserControlHolder is a place holder on the aspx page
// where I want to load the user control to
UserControlHolder.Controls.Add(myControl);
}
This works fine for me.
Here is the code for the dynamically loaded user control:
MyControl.ascx.cs
public partial class MyControl : System.Web.UI.UserControl
{
protected void Page_Init(object sender, EventArgs e)
{
LiteralControl lit = new LiteralControl("Test Literal Control");
Page.Controls.Add(lit);
}
protected void Page_Load(object sender, EventArgs e)
{
whatever.Visible = true;
if (IsPostBack)
{
whatever.Visible = false;
}
}
}