Purpose To Use The Delegates?
Mar 22, 2010what is the use of delegates. why we use delegates.
View 1 Replieswhat is the use of delegates. why we use delegates.
View 1 Replieswhy delegates are using in event handling?what is the advantages of using delegates in event handling?
View 4 RepliesI have a standard web app. My default page has a WebMethod and the WebMethod gets invoked by Json from client script. On my webForm I have an area that displays messages to the user showing the stage in the process and this is just a <asp:label>. if The webmethod had been a standard method, I would simply have done something like myLabel.Text = "sometext". However, the webMethod knows nothing about the label and so I need to bubble the value to the form. If I had called the webmethod from the codebehind in the form I may have been able to use delegates/events, but the call was made by the client, so I have not wired the webmethod up to any codebehind. How do I push my text back to the form in an asyncronous manner. So the code works in this way: Form load populates some controls on the client. The user perfoms some drag and drop then presses a standard html input button that calls a client ajax/json method passing the dragged values to the webmethod. I then need to feed back to the screen at several points in the webmethod process to inform the user of the current status.
View 5 Replies[Code]....
How to bind multiple delegates to an event?
I have an ASP.NET application and need to use some COM components inside it.
I need a wrapper class over Func or Action which creates a new STA thread and run the delegate with that thread or something like this. Do you know such a class or library out of the box or a sample code ?
CodeUsingComComponent.InvokeSTA()
Presently i used user control in my total application. i wrote single delegate , single event in to forms like this.
In User Control :
public delegate void onCloseClick();
public event onCloseClick OnCloseClick;
In Form :
In form load i declared --> this.devXToolRibbon1.OnCloseClick += new UBS.Phoenix.WinForm.Common.DevUI.DevXToolRibbon.onCloseClick(devXToolBar1_OnCloseClick);
i implemented event like this...
void devXToolBar1_OnCloseClick()
{
Form.close();
}
i know this much only about delegates & events... when we will bind multiple delegates to an event?
I'm using the mock framework to unit test some methods. I came across some methods that use delegates. I did not find a way to setup these delegates to return the objects that I want. The mock framework does not support it as far as I know. Is this supported in other mock frameworks like nMock?
View 3 RepliesCan somebody justify this statement with example: delegates represent methods that are callable without knowledge of the target object. i am not getting how we are hiding the function name at the UI.
View 4 Replieswhat i want to do is to get the current ip i have (with a site as, http://whatismyip.com/) and send it to paypal sandbox so i can get a response (of course i haven't started the paypal code but i first need to be able to get a communication from paypal,non?)Ok the problem is that if i start a new web site on IIS, hit the current ip, i get my router administration console as a response.I have tried to change the port on a new site to 81 or 82 or 83 but i get a page not found.
View 11 Replies<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" onrowediting="GridView1_RowEditing">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:Button ID="btnEdit" runat="server" Text="Edit" CommandName="Edit" />
<asp:Label ID="lblFirstColumn" runat="server" Text='<%# Eval("FirstColumn") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:Label ID="lblEditMode" runat="server" Text="This is Edit mode"></asp:Label>
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
protected void Page_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt.Columns.Add("FirstColumn", typeof(int));
dt.Rows.Add(100);
GridView1.DataSource = dt;
if (!IsPostBack)
GridView1.DataBind();
}
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
GridView1.EditIndex = e.NewEditIndex;
GridView1.DataBind();
}
If I change if (!IsPostBack) GridView1.DataBind(); to GridView1.DataBind(); and try to put GridView into Edit mode by clicking btnEdit, then I get the exception: Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. But if I set EnableEventValidation to false, then GridView1 won't enter edit mode ( ie - GridView1_RowEditing doesn't get called ). BTW - same problem also occurs with other databound controls ( DataList, DetailsView ) Page. EnableEventValidation gets or sets a value indicating whether the page validates postback and callback events. When the ableEventValidation property is set to true, ASP.NET validates that a control event originated from the user interface that was rendered by that control. A control registers its events during rendering and then validates the events during postback or callback handling.
a) Why must postback and callback events be evaluated? and how exactly does evaluation happen?
b) Why would calling GridView1.Databind() on each postback cause exception when trying to put it into edit mode?
c) I also don't see any reasons why disabling EnableEventValidation prevents GridView from entering edit mode?! Thus why did.
Can anyone tell me what does CAPTCHA do as far as security issue is concerned?Registration form of many sites have this field but how it works?
View 5 Repliesi want to know what is purpose of using masterpage?
View 5 Repliesi would like to know what the StringWriter Class is about and when we should use it.
View 2 Repliesfound a .gpState file in the folder,What is the purpose of gpState file?
View 2 Repliespurpose and mechanisms of the postback event? I am becoming very confusined when reading and am hoping that someone could explain it to a beginner.
View 17 RepliesWhat is the purpose of BrowserFile1.browser?
How to use it?
What is the purpose of Handler (.ashx files) and what is the use ?
can i get any sample ?
What is the purpose of the PropertySpecified pattern used by XML Serialization ?
View 1 RepliesI have a problem with URL of my application..................
I want to rewrite my url for security purpose......Like....
suppose my application URl is .....http://localhost/MyApplication/Product.aspx
But i want to change this url with......... http://localhost/MyApplication/MyProducts
In documentation I have read:
„Use the PostBackTrigger control to enable controls inside an UpdatePanel to cause a postback instead of performing an asynchronous postback."
I made simple application and I do not see difference between using PostBackTrigger and standard postback.
I have three buttons: two inside update panel and one outside update panel. When I click btnUpdateAsync in event handler I set text property of lblUpdatePanel and lblNoUpdatePanel and only lbl that is inside update panel is chaned if web browswer - so this is ok.
Whant I click btnUpdateInUpdatePanelSync all page is refreshed and both lablels are changed in web browser.
When I click btnUpdateOutsideUpdatePanel I see the same behavior.
If I used button that is not associated with PostBackTrigger I would get the same behavior - so what is the purpose of PostBackTrigger?
This is my app:
[Code]....
protected void Page_Load(object sender, EventArgs e)
{
}
protected void LinkButton1_Click(object sender, EventArgs e)
{
}
protected void btnUpdateAsync_Click(object sender, EventArgs e)
{
lblUpdatePanel.Text = "btnUpdateAsync_Click";
lblNoUpdatePanel.Text = "btnUpdateAsync_Click";
}
protected void btnUpdateInUpdatePanelSync_Click(object sender, EventArgs e)
{
lblUpdatePanel.Text = "btnUpdateInUpdatePanelSync_Click";
lblNoUpdatePanel.Text = "btnUpdateInUpdatePanelSync_Click";
}
protected void btnUpdateOutsideUpdatePanel_Click(object sender, EventArgs e)
{
lblUpdatePanel.Text = "btnUpdateInUpdatePanelSync_Click";
lblNoUpdatePanel.Text = "btnUpdateInUpdatePanelSync_Click";
}
i have to implement for online payment getting for donation for a social community
View 1 RepliesDuring a recent interview the following question was asked.
- A Master page which contains
- An ASPX web form page which contains
- A Web User Control inside the page which contains
- A button to fire some code in a button_click event
The Init Event will fire (Inner Most to Outer Most)
aspx.page Begin Init
-> Inside user control Page_Init
-> Inside master page Page_Init
-> Inside lifecycle page Page_Init
aspx.page End Init
and Load Event will fire
aspx.page Begin Load
-> Inside lifecycle page Page_Load
-> Inside master page Page_Load
-> Inside user control Page_Load
aspx.page End Load
Why does ASP.NET framework support different execution order in Load() and Init().This was the question asked in interview.I have no idea about what the interviewer expecting from me.
If you have a very large stored procedure, is it okay to just use the commands just once in the script?
ANSI_NULLS ON and QUOTED_IDENTIFIERS ON?I really don't understand the purpose of these commands?
What is the purpose and proper use of the max-length property on text fields?
The application I'm working on limits numeric fields to 6 characters... which doesn't work very well for entering millions of dollars... which is why I'm "fixing" it.
My understanding of Factory Method Pattern is (Correct me if i am wrong) Factory Method Pattern "Factory Method allow the client to delegates the product creation (Instance Creation) to the subclass". There are two situation in which we can go for creating Factory Method pattern.
(i) When the client is restricted to the product (Instance) creation.
(ii) There are multiple products available.But a decision to be made which product instance need to be returned. If you want to create Abstract Method pattern
You need to have abstract product Concrete Product Factory Method to return the appropriate product.
public enum ORMChoice
{
L2SQL,
EFM,
LS,
Sonic
}
//Abstract Product
public interface IProduct
{
void ProductTaken();
}
//Concrete Product
public class LinqtoSql : IProduct
{
public void ProductTaken()
{
Console.WriteLine("OR Mapping Taken:LinqtoSql");
}
}
//concrete product
public class Subsonic : IProduct
{
public void ProductTaken()
{
Console.WriteLine("OR Mapping Taken:Subsonic");
}
}
//concrete product
public class EntityFramework : IProduct
{
public void ProductTaken()
{
Console.WriteLine("OR Mapping Taken:EntityFramework");
}
}
//concrete product
public class LightSpeed : IProduct
{
public void ProductTaken()
{
Console.WriteLine("OR Mapping Taken :LightSpeed");
}
}
public class Creator
{
//Factory Method
public IProduct ReturnORTool(ORMChoice choice)
{
switch (choice)
{
case ORMChoice.EFM:return new EntityFramework();
break;
case ORMChoice.L2SQL:return new LinqtoSql();
break;
case ORMChoice.LS:return new LightSpeed();
break;
case ORMChoice.Sonic:return new Subsonic();
break;
default: return null;
}
}
}
**Client**
Button_Click()
{
Creator c = new Creator();
IProduct p = c.ReturnORTool(ORMChoice.L2SQL);
p.ProductTaken();
}
Is my understanding of Factory Method is correct?