ASP.NET

9-Jul-06 3:51

hi all,

i have created an custom server control that is rendered, i.e., not a composite control that is built in CreateChildControls(). My control extends WebControl and i have wired up the ClientScript.GetPostBackEventReference() but this doesnt work if javascript is disabled, obviously.

so i also wired up the Click event of the buttons in my control as a failsafe, but they never fire. can anyone please help with this.

the control is huge, so i will try and post the relevant code below.

the control is a message box and i only need to be concerned with the button click events.

protected override void OnInit(EventArgs e)
    {
      if (Draggable)
      {
        Page.ClientScript.RegisterClientScriptInclude(
          this.GetType(), "DragScript", Page.ClientScript.GetWebResourceUrl(this.GetType(),
           "WebMessageBox.Resources.DragScript.js"));
      }
      RenderEmbeddedStyleSheet(null);

      foreach (Button button in Buttons)
      {
        button.Attributes["onclick"] = Page.ClientScript.GetPostBackEventReference(this, button.Text);
        button.Click += new EventHandler(Button_Click);
      }
    }
#region ButtonClicked event

    protected void Button_Click(object sender, EventArgs e)
    {
      OnButtonClicked(new ButtonClickedArgs((Button)sender));
    }

    public delegate void ButtonClickedHandler(MessageBox sender, ButtonClickedArgs e);
    [
     Description("Fired when a button is clicked within the Message Box"),
     Category("Button")
    ]
    public event ButtonClickedHandler ButtonClicked;

    /// <summary>
    /// Fires the MessageBoxButtonClicked event
    /// </summary>
    protected void OnButtonClicked(ButtonClickedArgs e)
    {
      if (ButtonClicked != null)
      {
        ButtonClicked(this, e);

        // hide the message box
        this.Visible = false;
      }
    }

    #endregion
    
    #region IPostBackEventHandler Members

    public void RaisePostBackEvent(string eventArgument)
    {
      bool found = false;
      Button button = null;
      int i = 0;

      while (i < Buttons.Count && !found)
      {
        Button b = Buttons[i];
        if (b.Text == eventArgument)
        {
          found = true;
          button = b;
        }
        i++;
      }
      if (button != null)
      {
        OnButtonClicked(new ButtonClickedArgs(button));
      }
    }

    #endregion

kind regards,
g00fy

minhpc_bk9-Jul-06 16:45

9-Jul-06 16:45

Hi there,
Does your custom control implement the INamingContainer interface in order for the postback event Click to be routed to the child button control?

g00fyman9-Jul-06 16:52

9-Jul-06 16:52

yes it does,

public class MessageBox : WebControl, INamingContainer, IPostBackEventHandler

as posted earlier i am, adding the event handler in oninit(), do i also need to wire up the event in AddParsedSubObject() ?

regards,
g00fy

minhpc_bk9-Jul-06 17:13

9-Jul-06 17:13

How do you add the child buttons stored in the Buttons collection? Do they get declared between the opening and closing tags of the custom control in the web page? or do you dynamically declare somewhere else?

g00fyman9-Jul-06 17:26

9-Jul-06 17:26

the buttons are decalred in a button collection.

initially the button collection is instantiated like this

private ButtonCollection m_Buttons = new ButtonCollection();
    [
     PersistenceMode(PersistenceMode.InnerProperty),
     DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
     Editor(typeof(ButtonCollectionEditor), typeof(UITypeEditor)),
     Category("Message Box"),
     Description("The buttons that will appear on the Message Box"),
     NotifyParentProperty(true),
     RefreshProperties(RefreshProperties.All),
     Bindable(true)
    ]
    public ButtonCollection Buttons
    {
      get { return m_Buttons; }
    }

in the MessageBox class. There is also an enum to designate a predifned set of buttons that works like this

private MessageBoxType m_MessageBoxButtons = MessageBoxType.YesNoCancel;
    [
     Category("Message Box"),
     Description("The pre-defined type of Message Box you want to start with."),
     DefaultValue(MessageBoxType.YesNoCancel),
     Bindable(true),
     NotifyParentProperty(true)
    ]
    public MessageBoxType MessageBoxButtons
    {
      get { return m_MessageBoxButtons; }
      set
      {
        m_MessageBoxButtons = value;

        Button[] buttons = null;
        Button button = null;

        switch (m_MessageBoxButtons)
        {
          case MessageBoxType.YesNoCancel:

            buttons = new Button[3];

            button = new Button();
            button.ID = "YesButton_" + DateTime.Now.Millisecond;
            button.Text = "Yes";
            buttons[0] = button;

            button = new Button();
            button.ID = "NoButton_" + DateTime.Now.Millisecond;
            button.Text = "No";
            buttons[1] = button;

            button = new Button();
            button.ID = "CancelButton_" + DateTime.Now.Millisecond;
            button.Text = "Cancel";
            buttons[2] = button;

            m_Buttons = new ButtonCollection(buttons);

            break;

          case MessageBoxType.YesNoAbort:

            buttons = new Button[3];

            button = new Button();
            button.ID = "YesButton_" + DateTime.Now.Millisecond;
            button.Text = "Yes";
            buttons[0] = button;

            button = new Button();
            button.ID = "NoButton_" + DateTime.Now.Millisecond;
            button.Text = "No";
            buttons[1] = button;

            button = new Button();
            button.ID = "AbortButton_" + DateTime.Now.Millisecond;
            button.Text = "Abort";
            buttons[2] = button;

            m_Buttons = new ButtonCollection(buttons);

            break;

          case MessageBoxType.Custom:

            Buttons.Clear();
            break;
        }
      }
    }

then in OnInit() i wire up the events like this, i also tried wiring up the event for the buttins during render, but that didnt work either.

protected override void OnInit(EventArgs e)
    {
      if (Draggable)
      {
        Page.ClientScript.RegisterClientScriptInclude(
          this.GetType(), "DragScript", Page.ClientScript.GetWebResourceUrl(this.GetType(),
           "WebMessageBox.Resources.DragScript.js"));
      }
      RenderEmbeddedStyleSheet(null);

      foreach (Button button in Buttons)
      {
        button.Attributes["onclick"] = Page.ClientScript.GetPostBackEventReference(this, button.Text.Trim());
        button.Click += new EventHandler(Button_Click);
      }
    }

the ButtonCollection class extends CollectionBase and overrides the standard functions (add, this[int], delete, clear etc) so it is strongly typed.

kind regards,
g00fy

minhpc_bk9-Jul-06 18:24

9-Jul-06 18:24

There are a couple of things come to mind:

+ This code below makes the button's id not consistent:

button.ID = "NoButton_" + DateTime.Now.Millisecond;

so the event cannot be routed to the button properly.

+ Do you add these buttons to the parent custom control?

+ You have another option to fire up the custom event of the control by overriding the OnBubbleEvent method to capture the button's click event, then you can raise the custom event.

g00fyman9-Jul-06 18:41

9-Jul-06 18:41

hey thanx for all your help Big Grin | :-D

i didnt notice that ID property, that was redundant from something else i had done earlier.

I have made the following changes;
- fixed the buttosn ID property
- added each buttons to base.Controls (base == WebControl)
- overriden OnBubbleEvent()

i have left the call to base in the bubble event and tried to step through it but it never fires, any ideas.

protected override void OnInit(EventArgs e)
{
  if (Draggable)
  {
    Page.ClientScript.RegisterClientScriptInclude(
      this.GetType(), "DragScript", Page.ClientScript.GetWebResourceUrl(this.GetType(),
       "WebMessageBox.Resources.DragScript.js"));
  }
  RenderEmbeddedStyleSheet(null);

  foreach (Button button in Buttons)
  {
    base.Controls.Add(button);

    button.Attributes["onclick"] = Page.ClientScript.GetPostBackEventReference(this, button.Text.Trim());
    button.Click += new EventHandler(Button_Click);
  }
}


protected override bool OnBubbleEvent(object source, EventArgs args)
{
  return base.OnBubbleEvent(source, args);
}

btw when i get it going, do you need an ASP.NET 2.0 MesageBox control?

kind regards,
g00fy

g00fyman9-Jul-06 19:05

9-Jul-06 19:05

ok went back to basics (and my asp books) and discovered this;

this does not work

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebMessageBox
{
  [DefaultProperty("Text")]
  [ToolboxData("<{0}:TestParent runat=server></{0}:TestParent>")]
  public class TestParent : Control, INamingContainer
  {
    private Button button = new Button();

    protected override void OnInit(EventArgs e)
    {      
      button.Text = "New Button";
      button.ID = base.UniqueID;
      button.Click += new EventHandler(button_Click);
    }


    protected override void Render(HtmlTextWriter writer)
    {
      base.Controls.Add(button);
      base.Render(writer);
    }

    void button_Click(object sender, EventArgs e)
    {
      Button button = (Button)sender;
      string s = button.Text;
    }

  }
}

this does work

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebMessageBox
{
  [DefaultProperty("Text")]
  [ToolboxData("<{0}:TestComposite runat=server></{0}:TestComposite>")]
  public class TestComposite : WebControl, INamingContainer
  {
    void button_Click(object sender, EventArgs e)
    {
      Button button = (Button)sender;
      string s = button.Text;
    }

    protected override void CreateChildControls()
    {
      Button button = new Button();
      button.Text = "New Button";
      button.ID = base.UniqueID;
      button.Click += new EventHandler(button_Click);

      base.Controls.Add(button);
    }
  }
}

any ideas on getting a rendered control to fire server events, otherwise i will have to rewrite my render code into CreateChildControls()?

kind regards,
g00fy

g00fyman9-Jul-06 19:20

9-Jul-06 19:20

have changed my control to a composite control and all is good.

regs,
g00fy

minhpc_bk9-Jul-06 19:32

Re: event in custom control [modified]

9-Jul-06 19:32

The first case does not work as you add the dynamic button in the Render method which occurs after the postback event is processed in the control life cycle, so the event hanler does not execute. In the second case, you use the CreateChildControls method to add the child control, and this method makes sure that the child button is added to the control hierarchy before the postback event is processed, so it works. Generally speaking, you need to make sure that the child control is added to the parent (more general, the control hierarchy) and the handler is wired up to the event before the event is processed in order to make it run properly.

g00fyman9-Jul-06 20:59

9-Jul-06 20:59

thanks for all your help so far,

the trouble i am having now is that the control is not rendered design time properly when it is a composite control, the properties are not being refreshed, like when i set a button group to YesNoCancel, i get nothing until i switch from design to source view to deign again.

so i moved the logic to create control hierarchy into createchildcontrols() then in render i just render the table that createchildcontrols() creates. but now the events aren't firing again and i can't see why as the events are wired up in CreateChildControls() still.

any ideas on how i can get design time support refreshing display when i change a property or

sorry to be a pain.

kind regards,
g00fy

this is what i have now

private WebTable MessageBoxTable = null;

private WebTable BuildHierarchy()
{
  // actual message box to hold all controls
  WebTable table = new WebTable(1, 1);
  table.Style[HtmlTextWriterStyle.Position] = (Location == MessageBoxLocation.CentreWindow) ? "absolute" : "relative";

  WebTable content = new WebTable(3, 1);
  WebTable header = CreateTitleBarPanel();
  WebTable body = CreateBodyPanel();
  WebTable buttons = CreateButtonsPanel();
  WebTable footer = CreateFooterPanel();

  // title bar
  table[0, 0].Controls.Add(header);

  // message area
  content[0, 0].Controls.Add(body);
  content.Width = new Unit(100, UnitType.Percentage);

  // buttons area
  content[1, 0].HorizontalAlign = HorizontalAlign.Center;
  if (DesignMode && Buttons.Count == 0)
  {
    content[1, 0].Controls.Add(new LiteralControl("Use the Property Browser to add the Message Box Buttons"));
    content[1, 0].Font.Bold = true;
    content[1, 0].Font.Name = "Verdana";
    content[1, 0].Font.Size = new FontUnit(11, UnitType.Pixel);
  }
  else
  {
    content[1, 0].Controls.Add(buttons);
  }

  // footer area
  content[2, 0].Controls.Add(footer);

  table.ID = this.ID;
  if (Draggable)
  {
    // mandatory attribute to enable dragging of message box,
    // drag handle is restricted to the title bar
    header.Attributes["onmousedown"] = "dragStart(event, '" + this.UniqueID + "_" + table.ID + "')";
    header.Style[HtmlTextWriterStyle.Cursor] = "move";
  }

  table.Height = base.Height;
  table.Width = base.Width;
  table[0, 0].Controls.Add(content);

  SetMessageBoxLocation(ref table);
  ApplyEmbeddedCssClasses(ref table, ref content, ref header, ref body, ref buttons, ref footer);

  foreach (Button button in Buttons)
  {
    button.Click += new EventHandler(Button_Click);
  }
  return table;
}

protected override void CreateChildControls()
{
  MessageBoxTable = BuildHierarchy();
}

protected override void Render(HtmlTextWriter writer)
{
  HtmlLink link = GetEmbeddedStyleSheet();
  WebTable table = MessageBoxTable;

  base.Controls.Add(link);
  base.Controls.Add(table);

  link.RenderControl(writer);
  table.RenderControl(writer);
}

-- modified at 3:31 Monday 10th July, 2006

minhpc_bk10-Jul-06 17:11