Composite Controls, eventhandlers and knowing which control caused postback

M

Martin

Hi,

I have created a composite control that has a number of standard asp.net
controls on it that can themselves cause postbacks.
What i need to do in my composite control is to determine which consituent
control caused a postback.

for example a have a consituent controls with two buttons on it "button1"
and "button2"
I have registered my control for postbacks using
"Page.RegisterRequiresPostBack(this);"

I have include a dynamic handler for my buttons and registered this however
when I click the button the code in my dynamic handler does not get raised.

however, because I have implemented "IPostBackDataHandler " the event
"RaisePostDataChangedEvent()" does get raised however this seems to have no
information in it about which button was clicked all it tells me is that a
postback occured.

what ideally i need to do is get the dynamic button handlesr to work, can
any body give me any advice on this or point me to a good article that shows
how to run button handlers from within compsoite controls.
i have included my code below for anybody's reference. -- this is my entire
test user control.

many thanks in advance.

cheers

martin.

using System;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.ComponentModel;

using System.Collections.Specialized;

namespace CompositeControls

{

/// <summary>

/// Summary description for Compositecontrol.

/// </summary>

[DefaultProperty("Text"),

ToolboxData("<{0}:Compositecontrol runat=server></{0}:Compositecontrol>")]

public class Compositecontrol : System.Web.UI.WebControls.WebControl,
IPostBackDataHandler

{

private Panel pnl;

private string text;


[Bindable(true),

Category("Appearance"),

DefaultValue("")]

public string txtFirstName

{

get

{

return text;

}

set

{

text = value;

}

}

protected override void OnInit(EventArgs e)

{

base.OnInit(e);

if (Page != null)

Page.RegisterRequiresPostBack(this);

}



protected override void CreateChildControls()

{

System.Web.HttpContext.Current.Trace.Write("CreateChildControls()");

pnl = new Panel();

TextBox txtbox = new TextBox();

txtbox.ID = UniqueID;

txtbox.Text = txtFirstName;

pnl.Controls.Add(txtbox);

Button btn;

btn = new Button();

btn.Text = "Submit control 1";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +1;

pnl.Controls.Add(btn);

btn = new Button();

btn.Text = "Submit control 2";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +2;

pnl.Controls.Add(btn);

base.CreateChildControls();

}

private void btn_Click(object sender, EventArgs e)

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Button Click
from btn_Click !!!!*****");

System.Web.HttpContext.Current.Trace.Write("******GOT THE Button Click from
btn_Click !!!!*****");

}

/// <summary>

/// Render this control to the output parameter specified.

/// </summary>

/// <param name="output"> The HTML writer to write out to </param>

protected override void Render(HtmlTextWriter output)

{

System.Web.HttpContext.Current.Trace.Write("Render()");

pnl.RenderControl(output);

}

public virtual bool LoadPostData(string postDataKey,

NameValueCollection postCollection)

{

foreach (string s in postCollection)

{

System.Web.HttpContext.Current.Response.Write(s + " : value " +
postCollection.Get(s) + "<br>");

}

String presentValue = txtFirstName;

String postedValue = postCollection[postDataKey];

System.Web.HttpContext.Current.Response.Write(postDataKey.ToString());

if (presentValue == null || !presentValue.Equals(postedValue))

{


txtFirstName = postedValue;

return true;

}

return false;

}



public virtual void RaisePostDataChangedEvent()

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Event from
RaisePostDataChangedEvent!!!!*****<br>");

System.Web.HttpContext.Current.Response.Write("Need to deciede which control
event raised the postback<br>");

Control control = null;

string ctrlname = Page.Request.Params.Get("__EVENTTARGET");

if (ctrlname != null && ctrlname != string.Empty)

{

control = Page.FindControl(ctrlname);

}

else

{

foreach (string ctl in Page.Request.Form)

{

Control c = Page.FindControl(ctl);

if (c is System.Web.UI.WebControls.Button)

{

control = c;

break;

}

}

}

//System.Web.HttpContext.Current.Response.Write(ctrlname.ToString());

//OnValueChanged(EventArgs.Empty);

}

}

}
 
T

Teemu Keiski

Hi,

because the control contains postbacking child controls, it would need to
implement INamingContainer interface.

--
Teemu Keiski
ASP.NET MVP, AspInsider
Finland, EU


Martin said:
Hi,

I have created a composite control that has a number of standard asp.net
controls on it that can themselves cause postbacks.
What i need to do in my composite control is to determine which consituent
control caused a postback.

for example a have a consituent controls with two buttons on it "button1"
and "button2"
I have registered my control for postbacks using
"Page.RegisterRequiresPostBack(this);"

I have include a dynamic handler for my buttons and registered this
however
when I click the button the code in my dynamic handler does not get
raised.

however, because I have implemented "IPostBackDataHandler " the event
"RaisePostDataChangedEvent()" does get raised however this seems to have
no
information in it about which button was clicked all it tells me is that a
postback occured.

what ideally i need to do is get the dynamic button handlesr to work, can
any body give me any advice on this or point me to a good article that
shows
how to run button handlers from within compsoite controls.
i have included my code below for anybody's reference. -- this is my
entire
test user control.

many thanks in advance.

cheers

martin.

using System;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.ComponentModel;

using System.Collections.Specialized;

namespace CompositeControls

{

/// <summary>

/// Summary description for Compositecontrol.

/// </summary>

[DefaultProperty("Text"),

ToolboxData("<{0}:Compositecontrol runat=server></{0}:Compositecontrol>")]

public class Compositecontrol : System.Web.UI.WebControls.WebControl,
IPostBackDataHandler

{

private Panel pnl;

private string text;


[Bindable(true),

Category("Appearance"),

DefaultValue("")]

public string txtFirstName

{

get

{

return text;

}

set

{

text = value;

}

}

protected override void OnInit(EventArgs e)

{

base.OnInit(e);

if (Page != null)

Page.RegisterRequiresPostBack(this);

}



protected override void CreateChildControls()

{

System.Web.HttpContext.Current.Trace.Write("CreateChildControls()");

pnl = new Panel();

TextBox txtbox = new TextBox();

txtbox.ID = UniqueID;

txtbox.Text = txtFirstName;

pnl.Controls.Add(txtbox);

Button btn;

btn = new Button();

btn.Text = "Submit control 1";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +1;

pnl.Controls.Add(btn);

btn = new Button();

btn.Text = "Submit control 2";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +2;

pnl.Controls.Add(btn);

base.CreateChildControls();

}

private void btn_Click(object sender, EventArgs e)

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Button Click
from btn_Click !!!!*****");

System.Web.HttpContext.Current.Trace.Write("******GOT THE Button Click
from
btn_Click !!!!*****");

}

/// <summary>

/// Render this control to the output parameter specified.

/// </summary>

/// <param name="output"> The HTML writer to write out to </param>

protected override void Render(HtmlTextWriter output)

{

System.Web.HttpContext.Current.Trace.Write("Render()");

pnl.RenderControl(output);

}

public virtual bool LoadPostData(string postDataKey,

NameValueCollection postCollection)

{

foreach (string s in postCollection)

{

System.Web.HttpContext.Current.Response.Write(s + " : value " +
postCollection.Get(s) + "<br>");

}

String presentValue = txtFirstName;

String postedValue = postCollection[postDataKey];

System.Web.HttpContext.Current.Response.Write(postDataKey.ToString());

if (presentValue == null || !presentValue.Equals(postedValue))

{


txtFirstName = postedValue;

return true;

}

return false;

}



public virtual void RaisePostDataChangedEvent()

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Event from
RaisePostDataChangedEvent!!!!*****<br>");

System.Web.HttpContext.Current.Response.Write("Need to deciede which
control
event raised the postback<br>");

Control control = null;

string ctrlname = Page.Request.Params.Get("__EVENTTARGET");

if (ctrlname != null && ctrlname != string.Empty)

{

control = Page.FindControl(ctrlname);

}

else

{

foreach (string ctl in Page.Request.Form)

{

Control c = Page.FindControl(ctl);

if (c is System.Web.UI.WebControls.Button)

{

control = c;

break;

}

}

}

//System.Web.HttpContext.Current.Response.Write(ctrlname.ToString());

//OnValueChanged(EventArgs.Empty);

}

}

}
Click to expand...
 
M

Martin

Hi Teemu,

thanks for the reply,
I just done a quick search on INamingContainer and the document i found
said "This is a marker interface only."
I am not quite sure what this means.

can you offer any further advice or pointers in the right direction.

cheers

martin.

Teemu Keiski said:
Hi,

because the control contains postbacking child controls, it would need to
implement INamingContainer interface.

--
Teemu Keiski
ASP.NET MVP, AspInsider
Finland, EU


Martin said:
Hi,

I have created a composite control that has a number of standard asp.net
controls on it that can themselves cause postbacks.
What i need to do in my composite control is to determine which consituent
control caused a postback.

for example a have a consituent controls with two buttons on it "button1"
and "button2"
I have registered my control for postbacks using
"Page.RegisterRequiresPostBack(this);"

I have include a dynamic handler for my buttons and registered this
however
when I click the button the code in my dynamic handler does not get
raised.

however, because I have implemented "IPostBackDataHandler " the event
"RaisePostDataChangedEvent()" does get raised however this seems to have
no
information in it about which button was clicked all it tells me is that a
postback occured.

what ideally i need to do is get the dynamic button handlesr to work, can
any body give me any advice on this or point me to a good article that
shows
how to run button handlers from within compsoite controls.
i have included my code below for anybody's reference. -- this is my
entire
test user control.

many thanks in advance.

cheers

martin.

using System;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.ComponentModel;

using System.Collections.Specialized;

namespace CompositeControls

{

/// <summary>

/// Summary description for Compositecontrol.

/// </summary>

[DefaultProperty("Text"),

ToolboxData("<{0}:Compositecontrol
Click to expand...
runat=server> said:
public class Compositecontrol : System.Web.UI.WebControls.WebControl,
IPostBackDataHandler

{

private Panel pnl;

private string text;


[Bindable(true),

Category("Appearance"),

DefaultValue("")]

public string txtFirstName

{

get

{

return text;

}

set

{

text = value;

}

}

protected override void OnInit(EventArgs e)

{

base.OnInit(e);

if (Page != null)

Page.RegisterRequiresPostBack(this);

}



protected override void CreateChildControls()

{

System.Web.HttpContext.Current.Trace.Write("CreateChildControls()");

pnl = new Panel();

TextBox txtbox = new TextBox();

txtbox.ID = UniqueID;

txtbox.Text = txtFirstName;

pnl.Controls.Add(txtbox);

Button btn;

btn = new Button();

btn.Text = "Submit control 1";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +1;

pnl.Controls.Add(btn);

btn = new Button();

btn.Text = "Submit control 2";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +2;

pnl.Controls.Add(btn);

base.CreateChildControls();

}

private void btn_Click(object sender, EventArgs e)

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Button Click
from btn_Click !!!!*****");

System.Web.HttpContext.Current.Trace.Write("******GOT THE Button Click
from
btn_Click !!!!*****");

}

/// <summary>

/// Render this control to the output parameter specified.

/// </summary>

/// <param name="output"> The HTML writer to write out to </param>

protected override void Render(HtmlTextWriter output)

{

System.Web.HttpContext.Current.Trace.Write("Render()");

pnl.RenderControl(output);

}

public virtual bool LoadPostData(string postDataKey,

NameValueCollection postCollection)

{

foreach (string s in postCollection)

{

System.Web.HttpContext.Current.Response.Write(s + " : value " +
postCollection.Get(s) + "<br>");

}

String presentValue = txtFirstName;

String postedValue = postCollection[postDataKey];

System.Web.HttpContext.Current.Response.Write(postDataKey.ToString());

if (presentValue == null || !presentValue.Equals(postedValue))

{


txtFirstName = postedValue;

return true;

}

return false;

}



public virtual void RaisePostDataChangedEvent()

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Event from
RaisePostDataChangedEvent!!!!*****<br>");

System.Web.HttpContext.Current.Response.Write("Need to deciede which
control
event raised the postback<br>");

Control control = null;

string ctrlname = Page.Request.Params.Get("__EVENTTARGET");

if (ctrlname != null && ctrlname != string.Empty)

{

control = Page.FindControl(ctrlname);

}

else

{

foreach (string ctl in Page.Request.Form)

{

Control c = Page.FindControl(ctl);

if (c is System.Web.UI.WebControls.Button)

{

control = c;

break;

}

}

}

//System.Web.HttpContext.Current.Response.Write(ctrlname.ToString());

//OnValueChanged(EventArgs.Empty);

}

}

}
Click to expand...
Click to expand...
 
T

Teemu Keiski

It means that you don't implement any methods when implementing it
(interface doesn't include any methods, it just "marks" the type). Just add
the declaration.

public class Compositecontrol : System.Web.UI.WebControls.WebControl,
IPostBackDataHandler, INamingContainer

--
Teemu Keiski
ASP.NET MVP, AspInsider
Finland, EU



Martin said:
Hi Teemu,

thanks for the reply,
I just done a quick search on INamingContainer and the document i found
said "This is a marker interface only."
I am not quite sure what this means.

can you offer any further advice or pointers in the right direction.

cheers

martin.

Teemu Keiski said:
Hi,

because the control contains postbacking child controls, it would need to
implement INamingContainer interface.

--
Teemu Keiski
ASP.NET MVP, AspInsider
Finland, EU


Martin said:
Hi,

I have created a composite control that has a number of standard
asp.net
controls on it that can themselves cause postbacks.
What i need to do in my composite control is to determine which consituent
control caused a postback.

for example a have a consituent controls with two buttons on it "button1"
and "button2"
I have registered my control for postbacks using
"Page.RegisterRequiresPostBack(this);"

I have include a dynamic handler for my buttons and registered this
however
when I click the button the code in my dynamic handler does not get
raised.

however, because I have implemented "IPostBackDataHandler " the event
"RaisePostDataChangedEvent()" does get raised however this seems to
have
no
information in it about which button was clicked all it tells me is
that a
postback occured.

what ideally i need to do is get the dynamic button handlesr to work, can
any body give me any advice on this or point me to a good article that
shows
how to run button handlers from within compsoite controls.
i have included my code below for anybody's reference. -- this is my
entire
test user control.

many thanks in advance.

cheers

martin.

using System;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.ComponentModel;

using System.Collections.Specialized;

namespace CompositeControls

{

/// <summary>

/// Summary description for Compositecontrol.

/// </summary>

[DefaultProperty("Text"),

ToolboxData("<{0}:Compositecontrol
Click to expand...
runat=server> said:
public class Compositecontrol : System.Web.UI.WebControls.WebControl,
IPostBackDataHandler

{

private Panel pnl;

private string text;


[Bindable(true),

Category("Appearance"),

DefaultValue("")]

public string txtFirstName

{

get

{

return text;

}

set

{

text = value;

}

}

protected override void OnInit(EventArgs e)

{

base.OnInit(e);

if (Page != null)

Page.RegisterRequiresPostBack(this);

}



protected override void CreateChildControls()

{

System.Web.HttpContext.Current.Trace.Write("CreateChildControls()");

pnl = new Panel();

TextBox txtbox = new TextBox();

txtbox.ID = UniqueID;

txtbox.Text = txtFirstName;

pnl.Controls.Add(txtbox);

Button btn;

btn = new Button();

btn.Text = "Submit control 1";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +1;

pnl.Controls.Add(btn);

btn = new Button();

btn.Text = "Submit control 2";

btn.Click += new EventHandler(btn_Click);

btn.ID = UniqueID +2;

pnl.Controls.Add(btn);

base.CreateChildControls();

}

private void btn_Click(object sender, EventArgs e)

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Button Click
from btn_Click !!!!*****");

System.Web.HttpContext.Current.Trace.Write("******GOT THE Button Click
from
btn_Click !!!!*****");

}

/// <summary>

/// Render this control to the output parameter specified.

/// </summary>

/// <param name="output"> The HTML writer to write out to </param>

protected override void Render(HtmlTextWriter output)

{

System.Web.HttpContext.Current.Trace.Write("Render()");

pnl.RenderControl(output);

}

public virtual bool LoadPostData(string postDataKey,

NameValueCollection postCollection)

{

foreach (string s in postCollection)

{

System.Web.HttpContext.Current.Response.Write(s + " : value " +
postCollection.Get(s) + "<br>");

}

String presentValue = txtFirstName;

String postedValue = postCollection[postDataKey];

System.Web.HttpContext.Current.Response.Write(postDataKey.ToString());

if (presentValue == null || !presentValue.Equals(postedValue))

{


txtFirstName = postedValue;

return true;

}

return false;

}



public virtual void RaisePostDataChangedEvent()

{

System.Web.HttpContext.Current.Response.Write("******GOT THE Event from
RaisePostDataChangedEvent!!!!*****<br>");

System.Web.HttpContext.Current.Response.Write("Need to deciede which
control
event raised the postback<br>");

Control control = null;

string ctrlname = Page.Request.Params.Get("__EVENTTARGET");

if (ctrlname != null && ctrlname != string.Empty)

{

control = Page.FindControl(ctrlname);

}

else

{

foreach (string ctl in Page.Request.Form)

{

Control c = Page.FindControl(ctl);

if (c is System.Web.UI.WebControls.Button)

{

control = c;

break;

}

}

}

//System.Web.HttpContext.Current.Response.Write(ctrlname.ToString());

//OnValueChanged(EventArgs.Empty);

}

}

}
Click to expand...
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