Search results matching tag 'ICallbackEventHandler'

Wizard Control - Next Button -

aspcheetah — Mon, 14 Dec 2009 05:00:00 GMT

Hello all,

I have a question about Wizard control Next button at StartTemplateNavigation.

My requirement is that there is a textbox on start step that where user inputs a username. I then use icallbackeventhandler
to check if username exists on server and return the message. To do this, I have two buttons in the start navigation.
One says check username, another one is the next button. If a true message is returned to callback script, the next button is enabled and user can click the next button to move to next step.

What I would like to do, however, is to only use the next button and eliminate the check username button.

When next button is clicked, the next button should first invoke the callback script and return its results. Then,
if true is returned from server side, the next button should move to the next wizard step.

What I have right now involves two buttons (because for client callback iam using html button with no server side
events, whereas the next button has runat="server" attribute). How can i merge the username checking (using callback)
and moving to next wizardstep using only the Next Button?????

I have tried setting attributes of the check username button in code after results are returned from server (callback).
What I did was to add runat=server and onserverclick=method_name_of_next_button_handler. But it does not work.

Can you please share some insight on this?

Thanks
Dave

Long running task - asynchronously in background so that UI does not freeze

aspcheetah — Wed, 16 Sep 2009 04:00:00 GMT

Hi,

I am a newbie in ASP.NET, so please take this into consideration when replying to some of the questions that I have.

i) Asynchronous method calling and running a task in background are two different things. An asynchronous method like BeginXXX does not run in the background as default. Is my understanding correct? Please correct me and also give me some article to read on running a long task asynchronously in the background so the UI is not frozen for the user (or the page does not keep on showing loading in the status bar)

ii) I read some articles regarding AJAX style file uploads. However, in every single piece of code that I ran, the browser status bar started to show loading. From what I understand, AJAX style file uploads mean that the user does not see this loading in the browser itself - though we can show a progress bar or animated gif in the page. OR, is AJAX style uploading referring to something else?

iii) Do client callbacks cause postbacks? That is, if i read page.ispostback would it be true or false when i use client callbacks (icallbackeventhandler)

Thanks guys for your help.

ICallbackEventHandler updating page elements problem

mahdiprog — Wed, 16 Sep 2009 04:00:00 GMT

I have implemented a user control that uses ICallbackEventHandler.

the control do some actions and after that raise an event to page.

when I use this event in the page, every changes to page doesn't apply.

it seems it requeirs another callback to udate page.

this is the code:

public delegate void CodeChangedHandler(object sender, CodeChangedArgs e);
	public event CodeChangedHandler CodeChanged;
	public delegate void GridSelectedChangedHandler(object sender, GridSelectedChangedArgs e);
	public event GridSelectedChangedHandler GridSelectedChanged;
	public event RadComboBoxItemsRequestedEventHandler ComboItemsRequested;
	public event EventHandler FindButtonClick;
	public event RadComboBoxSelectedIndexChangedEventHandler SelectedIndexChanged;
	public event RadTreeViewEventHandler TreeNodeExpand;
	protected override void OnInit(EventArgs e)
	{
		base.OnInit(e);
		
		if (gridTemplate != null)
		{
			GridContainer container = new GridContainer();
			gridTemplate.InstantiateIn(container);
			phGrid.Controls.Add(container);
		}
		InitializeComponent();
	}
	private void InitializeComponent()
	{
		Load += new EventHandler(Page_Load);
		rcmbDescription.ItemsRequested += new RadComboBoxItemsRequestedEventHandler(rcmbDescription_ItemsRequested);
		rcmbDescription.SelectedIndexChanged += new RadComboBoxSelectedIndexChangedEventHandler(rcmbDescription_SelectedIndexChanged);
		lbtnFind.Click+=new EventHandler(lbtnFind_Click);
		rtvClasses.NodeExpand += new RadTreeViewEventHandler(rtvClasses_NodeExpand);
	}

	void rtvClasses_NodeExpand(object sender, RadTreeNodeEventArgs e)
	{
		if (TreeNodeExpand != null) TreeNodeExpand(sender, e);
	}

	void rcmbDescription_SelectedIndexChanged(object o, RadComboBoxSelectedIndexChangedEventArgs e)
	{
		if (SelectedIndexChanged != null) SelectedIndexChanged(o, e);
	}

	void grid_SelectedIdsComing(object sender, SelectedIdsComingArgs e)
	{
		SelectedItemIds = e.SelectedIds;
		long SelectedId = (SelectedItemIds.Length > 0 ? SelectedItemIds[0] : 0);
		if (SelectedItemIds.Length > 0 && GridSelectedChanged != null) GridSelectedChanged(sender, new GridSelectedChangedArgs(SelectedId));
		(phGrid.Controls[0].FindControl(GridId) as SelectableGrid).OnClientItemSelect=
			ID+"closePopup("+SelectedItemIds.Length+","+SelectedId.ToString()+",'"+SelectedItemTitle+ "','"+SelectedItemCode+"');";
	}

	void lbtnFind_Click(object sender, EventArgs e)
	{
		if (FindButtonClick != null) FindButtonClick(sender, e);
		if (ShowGrid)
		{
			SelectableGrid ThisGrid = (phGrid.Controls[0].FindControl(GridId) as SelectableGrid);
			ScriptManager.RegisterClientScriptBlock(Page, typeof(Page), "RegisterOnclick",
				"$('#"+ID+"btnSelect').click(function () {" + ThisGrid.RequestSelectedIdsFromClient() + "});", true);
			ThisGrid.OnClientRowDblClick = ThisGrid.RequestSelectedIdsFromClient();
		}
	}

	void rcmbDescription_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e)
	{
		ComboItemsRequested(o, e);
	}
	public string sCallBackFunctionInvocation;

	protected void Page_Load(object sender, EventArgs e)
	{
		sCallBackFunctionInvocation = Page.ClientScript.GetCallbackEventReference(this,
		  "message", ID + "processMyResult", "context", "postMyError", true);
		if (ShowGrid)
		{
			_grid = phGrid.Controls[0].FindControl(GridId) as SelectableGrid;
			_grid.SelectedIdsComing += new SelectableGrid.SelectedIdsComingHandler(grid_SelectedIdsComing);
		}
		if (!IsPostBack)
		{
			rtvClasses.Nodes.Clear();
			RadTreeNode node = new RadTreeNode();
			node.Text = TreeFirstElementName;
			node.Value = "0";
			node.ExpandMode = TreeNodeExpandMode.ServerSideCallBack;
			rtvClasses.Nodes.Add(node);
			rtvClasses.CheckBoxes = TreeCheckable;
			rtvClasses.CheckChildNodes = TreeCheckable;
			rtvClasses.OnClientDoubleClick = ID + "TreeDoubleClick";
			rtvClasses.OnClientLoad = ID + "TreeOnClientLoad";
			lbtnFind.OnClientClick = ID + "showPopup();";
			lbtnDeselect.OnClientClick = ID + "enableAll();";
			rcmbDescription.OnClientSelectedIndexChanged = ID + "ComboSelectedIndexChanged";
			txtCode.Attributes.Add("onchange", ID + "setDescriptionCombo();");
		}
	}

	#endregion
	public class CodeChangedArgs : EventArgs
	{
		private string _strCode;
		public string Code
		{
			get { return _strCode; }
		}
		public CodeChangedArgs(string strCode)
		{
			_strCode = strCode;
		}
	}
	public class GridSelectedChangedArgs : EventArgs
	{
		private long _lSerial;
		public long Serial
		{
			get { return _lSerial; }
		}
		public GridSelectedChangedArgs(long lSerial)
		{
			_lSerial = lSerial;
		}
	}

	#region ICallbackEventHandler Members
	public string GetCallbackResult()
	{
		return SelectedItemSerial.ToString()+"$"+SelectedItemTitle;
	}

	public void RaiseCallbackEvent(string eventArgument)
	{
		string[] eventArguments = eventArgument.Split(new char[] { '$' });

		if (eventArguments[0] == "setdescriptioncombo")
		{
			SelectedItemCode = eventArguments[1];
			if (CodeChanged != null) CodeChanged(txtCode, new CodeChangedArgs(SelectedItemCode));
		}
		if (eventArguments[0] == "selectedindexchanged")
		{
			SelectedItemCode = eventArguments[1];
			SelectedItemSerial = Convert.ToInt64(eventArguments[3]);
			SelectedItemTitle = eventArguments[2];
			if (SelectedIndexChanged != null) SelectedIndexChanged(rcmbDescription, new RadComboBoxSelectedIndexChangedEventArgs(eventArguments[2],"",eventArguments[3],""));
		}
	}
	#endregion

So what's your suggestion(s)?

Thanks In Advance.

Re: WebControl isn't working at all. Please help me. I have tryed it for several days..

dKorpar — Mon, 08 Jun 2009 04:00:00 GMT

try using ICallbackEventHandler...

also good link:
http://www.ajaxprojects.com/ajax/tutorialdetails.php?itemid=119

Issue with ICallbackEventHandler

renu.ap@gmail.com — Thu, 04 Jun 2009 04:00:00 GMT

Hi,

I am trying to render the contents of a panel to PDF using web user control that i have created.

In source page I am using ICallbackEventHandler. In downloaded PDF following text also coming inthe top of PDF

//var theForm = document.forms['aspnetForm']; if (!theForm) { theForm = document.aspnetForm; } function

__doPostBack(eventTarget, eventArgument) { if (!theForm.onsubmit || (theForm.onsubmit() != false)) {

theForm.__EVENTTARGET.value = eventTarget; theForm.__EVENTARGUMENT.value = eventArgument;

theForm.submit(); } } //

Please suggest......

ViewState problem with ICallbackEventHandler

Bonomi — Mon, 02 Mar 2009 05:00:00 GMT

Hi,

I'm trying to do a compositecontrol that fires a event and I can't preserve values in the viewstate on the page.

First, I click on Hello button and ViewState["myValue"] is set with "Hello" value, after that I press "Button" with a breakpoint in the Button1_Click event and I can see that ViewState["myValue"] is null, why? Any ideas?

Thanks

Here is the code:

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        mywc.Handler_MyEvent += new EventHandler(HandlerOnServer);
    }

    protected void HandlerOnServer(object sender, EventArgs e)
    {
        ViewState["myValue"] = "Hello";
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        String str = ViewState["myValue"];
    }
}

aspx file:

<cc1:MyWebControl runat="server" id="mywc"></cc1:MyWebControl>

<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />

Control code:

public class MyWebControl : CompositeControl, ICallbackEventHandler
    {
        public event EventHandler Handler_MyEvent;

        protected virtual void OnEventFired(EventArgs e)
        {
            if (Handler_MyEvent != null)
            {
                Handler_MyEvent(this, e);
            }
        }

        protected override void CreateChildControls()
        {
            HtmlInputButton ibutton = new HtmlInputButton();

            ibutton.Attributes["onclick"] = "clicked();";
            ibutton.Value = "save";
            Controls.Add(ibutton);
            ClientScriptManager cs = this.Page.ClientScript;


            if (!cs.IsClientScriptIncludeRegistered("MyJS"))
            {
                StringBuilder strScript = new StringBuilder();

                strScript.Append(@"<script type='text/javascript' >");
                strScript.Append(ClassLibDemo.Resource1.jscript);
                strScript.Append(@"</script>");

                cs.RegisterClientScriptBlock(this.GetType(), "MyJS", strScript.ToString());
            }

            String cbReference = cs.GetCallbackEventReference(this, "arg",
        "ReceiveDataFromServer", "context", "OnError", true);
            String callbackScript = "function SendDataToServer(arg, context) {" +
                cbReference + "; }";
            cs.RegisterClientScriptBlock(this.GetType(),
                "SendDataToServer", callbackScript, true);

        }

        #region ICallbackEventHandler Members

        public string GetCallbackResult()
        {
            return "enviado para o cliente";
        }

        public void RaiseCallbackEvent(string eventArgument)
        {
            String str = "recebido";
            OnEventFired(EventArgs.Empty);
        }

        #endregion
    }

Get values from a CompositeControl that implements ICallbackEventHandler

Bonomi — Mon, 02 Feb 2009 05:00:00 GMT

Hi people,

I have created a CompositeControl that implements the ICallbackEventHandler interface and
uses the RaiseCallbackEvent method for receiving data from client side and this value is
stored in a public property and a public event is raised to inform the page that the control
has a new value.
In debug mode I can see this value in the page, but when I assign the value to a textbox
(in a registered event handler on the page) I cannot see the result in the page, maybe
because the value is not firing the PreRender() event.
How can I get the value and show it on the page?

public class MyCompositeCtl : CompositeControl, ICallbackEventHandler
{
    public myValue;

    public event EventHandler Handler_ValueChanged;

    protected void TextBox_CoordinatesChanged(object sender, EventArgs e)
        {
            if (Handler_ValueChanged != null)
            {
                Handler_ValueChanged(this, e);
            }
        }

    void ICallbackEventHandler.RaiseCallbackEvent(string eventArgument)
        {
        myValue = eventArgument;
        Ctl_ValueChanged(this, EventArgs.Empty);
    }
}

Default.aspx
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        MyControl.Handler_ValueChanged +=
            new EventHandler(MyControl_ValueChanged);
    }


    protected void MyControl_ValueChanged(object sender, EventArgs e)
    {
        tbLat.Text = MyControl.myValue;
    }
    .....
}

Thanks to all.

Get values from a CompositeControl that implements ICallbackEventHandler

Bonomi — Sun, 01 Feb 2009 05:00:00 GMT

Hi people,

I have created a CompositeControl that implements the ICallbackEventHandler interface and
uses the RaiseCallbackEvent method for receiving data from client side and this value is
stored in a public property and a public event is raised to inform the page that the control
has a new value.
In debug mode I can see this value in the page, but when I assign the value to a textbox
(in a registered event handler on the page) I cannot see the result in the page, maybe
because the value is not firing the PreRender() event.
How can I get the value and show it on the page?

public class MyCompositeCtl : CompositeControl, ICallbackEventHandler
{
   public myValue;

   public event EventHandler Handler_ValueChanged;

   protected void TextBox_CoordinatesChanged(object sender, EventArgs e)
        {
            if (Handler_ValueChanged != null)
            {
                Handler_ValueChanged(this, e);
            }
        }

   void ICallbackEventHandler.RaiseCallbackEvent(string eventArgument)
        {
       myValue = eventArgument;
       Ctl_ValueChanged(this, EventArgs.Empty);
   }
}

Default.aspx
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        MyControl.Handler_ValueChanged +=
            new EventHandler(MyControl_ValueChanged);
    }


    protected void MyControl_ValueChanged(object sender, EventArgs e)
    {
        tbLat.Text = MyControl.myValue;
    }
    .....
}

Thanks to all.

ICallbackEventHandler and passing multiple string values to server and receiving multiple values

betamax — Sat, 24 Jan 2009 05:00:00 GMT

Hello,

I need some help with ICallbackEventHandler and was wondering if some experts can share their knowledge on this. Thanks in advance.

I am retrieving results from a web service that returns xml nodes. In order to return XML nodes to client, I have converted xmlnodes into string (string concatenation and returned one string to the client). Is there a way to return may be xml or JSON or even a string array using ICallbackEventHandler. Here is my complete code.

Imports net.ecubicle.www

Imports System.Xml.Linq

Partial Class driving_web_service

Inherits System.Web.UI.Page

Implements ICallbackEventHandler

Protected directions As String = String.Empty

Protected Sub Page_load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load

Dim cm As ClientScriptManager = Page.ClientScript

Dim cbReference As String = cm.GetCallbackEventReference(Me, "arg", "ReceiveServerData", "")

Dim callbackscript As String = "function CallServer(arg,context) {" & cbReference & ";}"

cm.RegisterClientScriptBlock(Me.GetType(), "CallServer", callbackscript, True)

' cm.RegisterClientScriptBlock(Me.GetType(), "SendValue", "function getDirections() { CallServer(document.getElementById('" & TextBox1.UniqueID & "').value + '* ' + document.getElementById('" & TextBox2.UniqueID & "').value,'')}", True)

cm.RegisterClientScriptBlock(Me.GetType(), "SendValue", _

"function getDirections() { " & _

"var myfrom=document.getElementById('" & TextBox1.UniqueID & "').value;" & _

"var myto=document.getElementById('" & TextBox2.UniqueID & "').value;" & _

"var completeaddress=myfrom + '*' + myto;" & _"CallServer(completeaddress,'');}", True)

End Sub

Public Function GetCallbackResult() As String Implements System.Web.UI.ICallbackEventHandler.GetCallbackResult Return directions

End Function

Public Sub RaiseCallbackEvent(ByVal eventArgument As String) Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent

Dim myNewDirectionsObject As New driving()

Dim AddressSplitter() As String = eventArgument.Split("*")

Dim FromAddress As String = AddressSplitter(0)

Dim ToAddress As String = AddressSplitter(1)

Dim myDirection As System.Xml.XmlNode = myNewDirectionsObject.GetDirections(FromAddress, ToAddress, "miles", "true")

Dim myXMLToString As String = myDirection.OuterXml

Dim myXdoc As XDocument = XDocument.Parse(myXMLToString)

Dim myDirectionsResult = From myResult In myXdoc.Descendants("route") _

Select myResult

For Each mySingleItem In myDirectionsResult directions = directions & "<br/>" & mySingleItem.Value

End Sub End Class

What I am doing in the above is to get values from two textboxes on the form and sending them to server in the form TEXTBOX1.TEXT*TEXTBOX2.TEXT. The server code then splits this into string array based on the * (asterik) and returns results to client in exactly the same manner (also embedding <br> tags after concatenating each result to the string). Then I just display the result in an HTML span which is defined as follows:

<span id="mydirections"></span>

The javascript to populate this span from server result is as follows:

Is there a way around this? Meaning, can I use arrays or any other way to pass around multiple values from client to server, and vice versa?

Thanks for your help in advance.

Regards,

Update panel problem in page in Raisepostbackevent

konda.chellu — Sat, 03 Jan 2009 05:00:00 GMT

Hi All,

I have one content form ManageAgencies.aspx page. In this page i have placed DualListBoxSelect user control in update panel.

This user control contains two list boxes and two button > and < to move content from one list box to another list box.

When we click on < button by selecting one item in left listbox.Before executing move function, for UI appearence I am moving item from leftlist box to right listbox.

move function logic pormpt one poup window and asking yes/no if we click no the items should be in there previous state. Here selected Item should go the left list box

This user control have one method MoveItem. From popup I am handling No button click event through RaisePostBackevent in the page ManageAgencies.aspx.cs file

In this event I am calling user control MoveItem method the function getting executed but the UI is not displaying the chnage.

That means the usercontrol in the aspx page is not refreshing .

How to refresh the usercontrol in the aspx page through RaisePostBackEvent

Thanks in advance

Konda