I have a Custom Web Control that is derived from Panel
. In my aspx markup for the control, I have a public event EventHandler
called SubmitButtonClicked
<cc1:CreditCard ID="CustomCreditCardPopupPanel" runat="server"
SubmitButtonClicked="CustomCreditCardPopupPanel_SubmitClick"> </cc1:CreditCard>
Here is the code for the custom web control (Shortened for clarity). When the web control is instantiated, the EventHandler SubmitButtonClicked
is always null. How do I pass in the name of the event that I want to bind to the Button
called BtnSubmit
?
[DefaultProperty("Text"),
AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal),
AspNetHostingPermission(SecurityAction.InheritanceDemand,
Level = AspNetHostingPermissionLevel.Minimal),
ToolboxData("<{0}:CreditCard runat=server></{0}:CreditCard>")
]
public class CreditCard: Panel {
public event EventHandler SubmitButtonClicked;
public Button BtnSubmit { get; set; }
protected override void OnPreRender(EventArgs e) {
base.OnPreRender(e);
this.BtnSubmit.Click += new EventHandler(SubmitButtonClicked); // SubmitButtonClicked is always null
}
protected void SubmitButtonClicked_Clicked(Object sender, EventArgs e) {
if (SubmitButtonClicked != null) {
SubmitButtonClicked(sender, e);
}
}
}
You must have
this.BtnSubmit.Click += new EventHandler(SubmitButtonClicked_Clicked);
And also, OnPreRender
event could be too late. Maybe you should assign the button event in Init, or Load event
Turns out that the best way to handle what I want to do is to derive my class from CompositeControl.
Example from Link:
// Register.cs
using System;
using System.ComponentModel;
using System.Drawing;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Samples.AspNet.CS.Controls
{
[
AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal),
AspNetHostingPermission(SecurityAction.InheritanceDemand,
Level=AspNetHostingPermissionLevel.Minimal),
DefaultEvent("Submit"),
DefaultProperty("ButtonText"),
ToolboxData("<{0}:Register runat=\"server\"> </{0}:Register>"),
]
public class Register : CompositeControl
{
private Button submitButton;
private TextBox nameTextBox;
private Label nameLabel;
private TextBox emailTextBox;
private Label emailLabel;
private RequiredFieldValidator emailValidator;
private RequiredFieldValidator nameValidator;
private static readonly object EventSubmitKey =
new object();
// The following properties are delegated to
// child controls.
[
Bindable(true),
Category("Appearance"),
DefaultValue(""),
Description("The text to display on the button.")
]
public string ButtonText
{
get
{
EnsureChildControls();
return submitButton.Text;
}
set
{
EnsureChildControls();
submitButton.Text = value;
}
}
[
Bindable(true),
Category("Default"),
DefaultValue(""),
Description("The user name.")
]
public string Name
{
get
{
EnsureChildControls();
return nameTextBox.Text;
}
set
{
EnsureChildControls();
nameTextBox.Text = value;
}
}
[
Bindable(true),
Category("Appearance"),
DefaultValue(""),
Description(
"Error message for the name validator.")
]
public string NameErrorMessage
{
get
{
EnsureChildControls();
return nameValidator.ErrorMessage;
}
set
{
EnsureChildControls();
nameValidator.ErrorMessage = value;
nameValidator.ToolTip = value;
}
}
[
Bindable(true),
Category("Appearance"),
DefaultValue(""),
Description("The text for the name label.")
]
public string NameLabelText
{
get
{
EnsureChildControls();
return nameLabel.Text;
}
set
{
EnsureChildControls();
nameLabel.Text = value;
}
}
[
Bindable(true),
Category("Default"),
DefaultValue(""),
Description("The e-mail address.")
]
public string Email
{
get
{
EnsureChildControls();
return emailTextBox.Text;
}
set
{
EnsureChildControls();
emailTextBox.Text = value;
}
}
[
Bindable(true),
Category("Appearance"),
DefaultValue(""),
Description(
"Error message for the e-mail validator.")
]
public string EmailErrorMessage
{
get
{
EnsureChildControls();
return emailValidator.ErrorMessage;
}
set
{
EnsureChildControls();
emailValidator.ErrorMessage = value;
emailValidator.ToolTip = value;
}
}
[
Bindable(true),
Category("Appearance"),
DefaultValue(""),
Description("The text for the e-mail label.")
]
public string EmailLabelText
{
get
{
EnsureChildControls();
return emailLabel.Text;
}
set
{
EnsureChildControls();
emailLabel.Text = value;
}
}
// The Submit event.
[
Category("Action"),
Description("Raised when the user clicks the button.")
]
public event EventHandler Submit
{
add
{
Events.AddHandler(EventSubmitKey, value);
}
remove
{
Events.RemoveHandler(EventSubmitKey, value);
}
}
// The method that raises the Submit event.
protected virtual void OnSubmit(EventArgs e)
{
EventHandler SubmitHandler =
(EventHandler)Events[EventSubmitKey];
if (SubmitHandler != null)
{
SubmitHandler(this, e);
}
}
// Handles the Click event of the Button and raises
// the Submit event.
private void _button_Click(object source, EventArgs e)
{
OnSubmit(EventArgs.Empty);
}
protected override void RecreateChildControls()
{
EnsureChildControls();
}
protected override void CreateChildControls()
{
Controls.Clear();
nameLabel = new Label();
nameTextBox = new TextBox();
nameTextBox.ID = "nameTextBox";
nameValidator = new RequiredFieldValidator();
nameValidator.ID = "validator1";
nameValidator.ControlToValidate = nameTextBox.ID;
nameValidator.Text = "Failed validation.";
nameValidator.Display = ValidatorDisplay.Static;
emailLabel = new Label();
emailTextBox = new TextBox();
emailTextBox.ID = "emailTextBox";
emailValidator = new RequiredFieldValidator();
emailValidator.ID = "validator2";
emailValidator.ControlToValidate =
emailTextBox.ID;
emailValidator.Text = "Failed validation.";
emailValidator.Display = ValidatorDisplay.Static;
submitButton = new Button();
submitButton.ID = "button1";
submitButton.Click
+= new EventHandler(_button_Click);
this.Controls.Add(nameLabel);
this.Controls.Add(nameTextBox);
this.Controls.Add(nameValidator);
this.Controls.Add(emailLabel);
this.Controls.Add(emailTextBox);
this.Controls.Add(emailValidator);
this.Controls.Add(submitButton);
}
protected override void Render(HtmlTextWriter writer)
{
AddAttributesToRender(writer);
writer.AddAttribute(
HtmlTextWriterAttribute.Cellpadding,
"1", false);
writer.RenderBeginTag(HtmlTextWriterTag.Table);
writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
nameLabel.RenderControl(writer);
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
nameTextBox.RenderControl(writer);
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
nameValidator.RenderControl(writer);
writer.RenderEndTag();
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
emailLabel.RenderControl(writer);
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
emailTextBox.RenderControl(writer);
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
emailValidator.RenderControl(writer);
writer.RenderEndTag();
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.AddAttribute(
HtmlTextWriterAttribute.Colspan,
"2", false);
writer.AddAttribute(
HtmlTextWriterAttribute.Align,
"right", false);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
submitButton.RenderControl(writer);
writer.RenderEndTag();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
writer.Write(" ");
writer.RenderEndTag();
writer.RenderEndTag();
writer.RenderEndTag();
}
}
}
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