Can't set value to the property "Width" of my custom webcontrol

jkartush

Can't set value to the property "Width" of my custom webcontrol

Web Programming66
This is a multi-part message in MIME format.

------=_NextPart_000_003D_01C83334.07BF4270

Content-Type: text/plain;

charset="gb2312"

Content-Transfer-Encoding: quoted-printable

=20

In webform.aspx: <cc:ctlB ID=3D"ctl1" runat=3D"server" Width=3D"200px" =

/>

If set value to width property, I will get a error that say ctlB.Page is =

null. This control will be fine with no width property, why?

Could anybody help me ? thanks

ctlA.cs

----------------------------

[

AspNetHostingPermission(SecurityAction.Demand, Level =3D =

AspNetHostingPermissionLevel.Minimal),

AspNetHostingPermission(SecurityAction.InheritanceDemand, Level =3D =

AspNetHostingPermissionLevel.Minimal),

DefaultProperty("Text"),

ValidationProperty("Text"),

ToolboxData("<{0}:ctlA runat=3D\"server\"></{0}:ctlA>")

]

public class ctlA : WebControl, INamingContainer

{

protected TextBox _textBox;

protected HiddenField _hiddenBox;

[Bindable(false), DefaultValue(""), =

TypeConverter(typeof(UnitConverter))]

public override Unit Width

{

get

{

EnsureChildControls();

return this._textBox.Width;

}

set

{

EnsureChildControls();

this._textBox.Width =3D value;

}

}

public override bool EnableViewState

{

get

{

EnsureChildControls();

return this._textBox.EnableViewState;

}

set

{

EnsureChildControls();

this._textBox.EnableViewState =3D value;

this._hiddenBox.EnableViewState =3D value;

this.EnableViewState =3D value;

}

}

protected override void CreateChildControls()

{

this._textBox =3D new TextBox();

this._textBox.ID =3D "Name";

this._textBox.ReadOnly =3D this.ReadOnly;

this._hiddenBox =3D new HiddenField();

this._hiddenBox.ID =3D "Value";

this.Controls.Add(this._textBox);

this.Controls.Add(this._hiddenBox);

}

protected override void Render(HtmlTextWriter writer)

{

EnsureChildControls();

base.Render(writer);

}

public override ControlCollection Controls

{

get

{

EnsureChildControls();

return base.Controls;

}

}

public ctlA()

: base(HtmlTextWriterTag.Span)

{

}

}

-------------------------------------------------------------------------=

-------

ctlB.cs

------------------------------

[ToolboxData("<{0}:ctlB runat=3D\"server\"></{0}:ctlB>")]

public class ctlB : ctlA

{

internal Image _schImage;

public ctlB()

: base()

{

}

protected override void CreateChildControls()

{

base.CreateChildControls();

this._schImage =3D new Image();

this._schImage.ID =3D "imgButton";

this._schImage.Attributes["align"] =3D "absmiddle";

this._schImage.Attributes["onclick"] =3D =

String.Format("__OpenDialog('{0}', null, {1}, {2}, '{3}', '{4}', {5});",

Page.ResolveUrl(this.DialogPagePath), =

this.DialogWidth.ToString(), this.DialogHeight.ToString(), =

this._textBox.ClientID, this._hiddenBox.ClientID, (this.DialogMode =

=3D=3D DialogMode.Model) ? "true" : "false");

this.Controls.Add(_schImage);

}

protected override void OnPreRender(EventArgs e)

{

base.OnPreRender(e);

=

this.Page.ClientScript.RegisterClientScriptResource(this.GetType(), =

"OpenDialog.js");

}

public override ControlCollection Controls

{

get

{

EnsureChildControls();

return base.Controls;

}

}

}

------=_NextPart_000_003D_01C83334.07BF4270

Content-Type: text/html;

charset="gb2312"

Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<HTML><HEAD>

<META http-equiv=3DContent-Type content=3D"text/html; charset=3Dgb2312">

<META content=3D"MSHTML 6.00.6000.16546" name=3DGENERATOR>

<STYLE></STYLE>

</HEAD>

<BODY>

<DIV> 

<DIV>In webform.aspx:  <FONT=20

color=3D#800000><cc:ctlB ID=3D"ctl1" =

runat=3D"server" Width=3D"200px"=20

/></DIV>

<DIV> </DIV>

<DIV>If set value to width property, I will get a error =

that say=20

ctlB.Page is null. This control will be fine with no width property,=20

why?</DIV>

<DIV> </DIV>

<DIV>Could anybody help me ? thanks</DIV>

<DIV> </DIV>

<DIV> </DIV>

<DIV> </DIV>

<DIV>ctlA.cs</DIV>

<DIV>----------------------------</DIV>

<DIV>[ AspNetHostingPermission(SecurityAction.Demand, Level <SPAN=20

style=3D"COLOR: #000000">=3D=20

AspNetHostingPermissionLevel.Minimal), AspNetHostingPermission(Securit=

yAction.InheritanceDemand,=20

Level =3D=20

AspNetHostingPermissionLevel.Minimal), DefaultProperty(<SPAN=20

style=3D"COLOR: #800000">"Text<SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: #000000">), ValidationProperty(<SPAN=20

style=3D"COLOR: #800000">"Text<SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: #000000">), ToolboxData(<SPAN=20

style=3D"COLOR: #800000">"<{0}:ctlA=20

runat=3D\"server\"> </{0}:ctlA><SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: #000000">) ] <SPAN=20

style=3D"COLOR: #0000ff">public=

<SPAN=20

style=3D"COLOR: #0000ff">class=

ctlA :=20

WebControl, INamingContainer {     <SPAN=20

style=3D"COLOR: #0000ff">protected=

TextBox=20

_textBox;     <SPAN=20

style=3D"COLOR: #0000ff">protected=

HiddenField=20

_hiddenBox;     [Bindable(<SPAN=20

style=3D"COLOR: #0000ff">false),=20

DefaultValue(""<SPAN=20

style=3D"COLOR: #000000">), TypeConverter(<SPAN=20

style=3D"COLOR: #0000ff">typeof<SPAN=20

style=3D"COLOR: #000000">(UnitConverter))]     =

<SPAN=20

style=3D"COLOR: #0000ff">public=

<SPAN=20

style=3D"COLOR: #0000ff">override=

Unit=20

Width     =

{        =20

get<SPAN=20

style=3D"COLOR: #000000">        =20

{            =20

EnsureChildControls();        &nbsp=

;   =20

return=20

this<SPAN=20

style=3D"COLOR: =

#000000">._textBox.Width;        =20

}         <SPAN=20

style=3D"COLOR: #0000ff">set<SPAN=20

style=3D"COLOR: #000000">        =20

{            =20

EnsureChildControls();        &nbsp=

;   =20

this<SPAN=20

style=3D"COLOR: #000000">._textBox.Width <SPAN=20

style=3D"COLOR: #000000">=3D=20

value;         =

}    =20

}     <SPAN=20

style=3D"COLOR: #0000ff">public=

<SPAN=20

style=3D"COLOR: #0000ff">override=

<SPAN=20

style=3D"COLOR: #0000ff">bool=20

EnableViewState    =20

{         <SPAN=20

style=3D"COLOR: #0000ff">get<SPAN=20

style=3D"COLOR: #000000">        =20

{            =20

EnsureChildControls();        &nbsp=

;   =20

return=20

this<SPAN=20

style=3D"COLOR: =

#000000">._textBox.EnableViewState;      &nbs=

p; =20

}         <SPAN=20

style=3D"COLOR: #0000ff">set<SPAN=20

style=3D"COLOR: #000000">        =20

{            =20

EnsureChildControls();        &nbsp=

;   =20

this<SPAN=20

style=3D"COLOR: #000000">._textBox.EnableViewState <SPAN=20

style=3D"COLOR: #000000">=3D=20

value;           &nb=

sp;=20

this<SPAN=20

style=3D"COLOR: #000000">._hiddenBox.EnableViewState <SPAN=20

style=3D"COLOR: #000000">=3D=20

value;           &nb=

sp;=20

this<SPAN=20

style=3D"COLOR: #000000">.EnableViewState <SPAN=20

style=3D"COLOR: #000000">=3D=20

value;         =

}    =20

}     <SPAN=20

style=3D"COLOR: #0000ff">protected=

override=20

void=20

CreateChildControls()    =20

{         <SPAN=20

style=3D"COLOR: #0000ff">this._textBox=20

=3D=20

new=20

TextBox();         <SPAN=20

style=3D"COLOR: #0000ff">this._textBox.ID=20

=3D=20

"<SPAN=20

style=3D"COLOR: #800000">Name"<SPAN=20

style=3D"COLOR: #000000">;         =

this<SPAN=20

style=3D"COLOR: #000000">._textBox.ReadOnly <SPAN=20

style=3D"COLOR: #000000">=3D=

<SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: =

#000000">.ReadOnly;        =20

this<SPAN=20

style=3D"COLOR: #000000">._hiddenBox <SPAN=20

style=3D"COLOR: #000000">=3D=

<SPAN=20

style=3D"COLOR: #0000ff">new=20

HiddenField();         =

<SPAN=20

style=3D"COLOR: #0000ff">this._hiddenBox.ID=20

=3D=20

"<SPAN=20

style=3D"COLOR: #800000">Value"<SPAN=20

style=3D"COLOR: =

#000000">;        =20

this<SPAN=20

style=3D"COLOR: #000000">.Controls.Add(<SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: =

#000000">._textBox);        =20

this<SPAN=20

style=3D"COLOR: #000000">.Controls.Add(<SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: #000000">._hiddenBox);    =20

}     <SPAN=20

style=3D"COLOR: #0000ff">protected=

override=20

void=20

Render(HtmlTextWriter writer)    =20

{        =20

EnsureChildControls();        =20

base<SPAN=20

style=3D"COLOR: #000000">.Render(writer);    =20

}     <SPAN=20

style=3D"COLOR: #0000ff">public=

<SPAN=20

style=3D"COLOR: #0000ff">override=20

ControlCollection Controls    =20

{         <SPAN=20

style=3D"COLOR: #0000ff">get<SPAN=20

style=3D"COLOR: #000000">        =20

{            =20

EnsureChildControls();        &nbsp=

;   =20

return=20

base<SPAN=20

style=3D"COLOR: =

#000000">.Controls;        =20

}     }     <SPAN=20

style=3D"COLOR: #0000ff">public=20

ctlA()         : <SPAN=20

style=3D"COLOR: #0000ff">base<SPAN=20

style=3D"COLOR: #000000">(HtmlTextWriterTag.Span)    =20

{     } } </DIV>

<DIV>

<HR>

</DIV>

<DIV><FONT=20

size=3D3>ctlB.cs</DIV>

<DIV><FONT=20

size=3D3>------------------------------</DIV>

<DIV> </DIV>

<DIV>[ToolboxData(<SPAN=20

style=3D"COLOR: #800000">"<{0}:ctlB=20

runat=3D\"server\"> </{0}:ctlB><SPAN=20

style=3D"COLOR: #800000">")] <SPAN=20

style=3D"COLOR: #0000ff">public=

<SPAN=20

style=3D"COLOR: #0000ff">class=

ctlB :=20

ctlA {     <SPAN=20

style=3D"COLOR: #0000ff">internal=

Image=20

_schImage;     <SPAN=20

style=3D"COLOR: #0000ff">public=20

ctlB()         : <SPAN=20

style=3D"COLOR: #0000ff">base<SPAN=20

style=3D"COLOR: #000000">()     =

{    =20

}     <SPAN=20

style=3D"COLOR: #0000ff">protected=

override=20

void=20

CreateChildControls()    =20

{         <SPAN=20

style=3D"COLOR: #0000ff">base<SPAN=20

style=3D"COLOR: =

#000000">.CreateChildControls();      &nb=

sp; =20

this<SPAN=20

style=3D"COLOR: #000000">._schImage <SPAN=20

style=3D"COLOR: #000000">=3D=

<SPAN=20

style=3D"COLOR: #0000ff">new=20

Image();         <SPAN=20

style=3D"COLOR: #0000ff">this._schImage.ID=20

=3D=20

"<SPAN=20

style=3D"COLOR: #800000">imgButton<SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: #000000">;         =

this<SPAN=20

style=3D"COLOR: #000000">._schImage.Attributes[<SPAN=20

style=3D"COLOR: #800000">"align<SPAN=20

style=3D"COLOR: #800000">"] =

<SPAN=20

style=3D"COLOR: #000000">=3D=

<SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: #800000">absmiddle<SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: =

#000000">;        =20

this<SPAN=20

style=3D"COLOR: #000000">._schImage.Attributes[<SPAN=20

style=3D"COLOR: #800000">"onclick<SPAN=20

style=3D"COLOR: #800000">"] =

<SPAN=20

style=3D"COLOR: #000000">=3D=20

String.Format("<SPAN=20

style=3D"COLOR: #800000">__OpenDialog('{0}', null, {1}, {2}, '{3}', =

'{4}',=20

{5});"<SPAN=20

style=3D"COLOR: #000000">,         =

Page.ResolveUrl(this<SPAN=20

style=3D"COLOR: #000000">.DialogPagePath), <SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: #000000">.DialogWidth.ToString(), <SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: #000000">.DialogHeight.ToString(), <SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: #000000">._textBox.ClientID, <SPAN=20

style=3D"COLOR: #0000ff">this<SPAN=20

style=3D"COLOR: #000000">._hiddenBox.ClientID, (<SPAN=20

style=3D"COLOR: #0000ff">this.DialogMode=20

=3D=3D=20

DialogMode.Model) ?<SPAN=20

style=3D"COLOR: #000000">"<SPAN=20

style=3D"COLOR: #800000">true"<SPAN=20

style=3D"COLOR: #000000">: "<SPAN=20

style=3D"COLOR: #800000">false"<SPAN=20

style=3D"COLOR: =

#000000">);        =20

this<SPAN=20

style=3D"COLOR: #000000">.Controls.Add(_schImage);     =

}     <SPAN=20

style=3D"COLOR: #0000ff">protected=

override=20

void=20

OnPreRender(EventArgs e)    =20

{         <SPAN=20

style=3D"COLOR: #0000ff">base<SPAN=20

style=3D"COLOR: =

#000000">.OnPreRender(e);        =20

this<SPAN=20

style=3D"COLOR: =

#000000">.Page.ClientScript.RegisterClientScriptResource(<SPAN=20

style=3D"COLOR: #0000ff">this.GetType(),=20

"<SPAN=20

style=3D"COLOR: #800000">OpenDialog.js<SPAN=20

style=3D"COLOR: #800000">"<SPAN=20

style=3D"COLOR: #000000">);     =

}    =20

public=20

override=20

ControlCollection Controls    =20

{         <SPAN=20

style=3D"COLOR: #0000ff">get<SPAN=20

style=3D"COLOR: #000000">        =20

{            =20

EnsureChildControls();        &nbsp=

;   =20

return=20

base<SPAN=20

style=3D"COLOR: =

#000000">.Controls;        =20

}     } } </DIV>

<DIV><SPAN=20

style=3D"COLOR: =

#000000"> </DIV></DIV></BODY></HTML>

------=_NextPart_000_003D_01C83334.07BF4270--

-

bruce

Registered User

Thu Nov 29 18:46:37 PST 2007

Re:Can't set value to the property "Width" of my custom webcontrol

simple, your CreateChildControls references Page before it has been set.

your control should handle being created and its properties set before

being added to the Pages control collection. to work in a designer it

should handle nopage and no request.

defer references to other controls (like the page) until prerender or

render.

-- bruce (sqlwork.com)

Brook wrote:

Quote

In webform.aspx: <cc:ctlB ID="ctl1" runat="server" Width="200px" />

If set value to width property, I will get a error that say ctlB.Page is

null. This control will be fine with no width property, why?

Could anybody help me ? thanks

*ctlA.cs*

*----------------------------*

[

AspNetHostingPermission(SecurityAction.Demand, Level =

AspNetHostingPermissionLevel.Minimal),

AspNetHostingPermission(SecurityAction.InheritanceDemand, Level =

AspNetHostingPermissionLevel.Minimal),

DefaultProperty("Text"),

ValidationProperty("Text"),

ToolboxData("<{0}:ctlA runat=\"server\"></{0}:ctlA>")

]

public class ctlA : WebControl, INamingContainer

{

protected TextBox _textBox;

protected HiddenField _hiddenBox;

[Bindable(false), DefaultValue(""),

TypeConverter(typeof(UnitConverter))]

public override Unit Width

{

get

{

EnsureChildControls();

return this._textBox.Width;

}

set

{

EnsureChildControls();

this._textBox.Width = value;

}

}

public override bool EnableViewState

{

get

{

EnsureChildControls();

return this._textBox.EnableViewState;

}

set

{

EnsureChildControls();

this._textBox.EnableViewState = value;

this._hiddenBox.EnableViewState = value;

this.EnableViewState = value;

}

}

protected override void CreateChildControls()

{

this._textBox = new TextBox();

this._textBox.ID = "Name";

this._textBox.ReadOnly = this.ReadOnly;

this._hiddenBox = new HiddenField();

this._hiddenBox.ID = "Value";

this.Controls.Add(this._textBox);

this.Controls.Add(this._hiddenBox);

}

protected override void Render(HtmlTextWriter writer)

{

EnsureChildControls();

base.Render(writer);

}

public override ControlCollection Controls

{

get

{

EnsureChildControls();

return base.Controls;

}

}

public ctlA()

: base(HtmlTextWriterTag.Span)

{

}

}

------------------------------------------------------------------------

*ctlB.cs*

*------------------------------*

[ToolboxData("<{0}:ctlB runat=\"server\"></{0}:ctlB>")]

public class ctlB : ctlA

{

internal Image _schImage;

public ctlB()

: base()

{

}

protected override void CreateChildControls()

{

base.CreateChildControls();

this._schImage = new Image();

this._schImage.ID = "imgButton";

this._schImage.Attributes["align"] = "absmiddle";

this._schImage.Attributes["onclick"] =

String.Format("__OpenDialog('{0}', null, {1}, {2}, '{3}', '{4}', {5});",

Page.ResolveUrl(this.DialogPagePath),

this.DialogWidth.ToString(), this.DialogHeight.ToString(),

this._textBox.ClientID, this._hiddenBox.ClientID, (this.DialogMode ==

DialogMode.Model) ? "true" : "false");

this.Controls.Add(_schImage);

}

protected override void OnPreRender(EventArgs e)

{

base.OnPreRender(e);

this.Page.ClientScript.RegisterClientScriptResource(this.GetType(),

"OpenDialog.js");

}

public override ControlCollection Controls

{

get

{

EnsureChildControls();

return base.Controls;

}

}

}

-

Brook

Registered User

Sat Dec 01 20:37:46 PST 2007

Re:Can't set value to the property "Width" of my custom webcontrol

thank you, bruce!

the problem be solved by your help.

But i can't read embeded resource with no page object.

this._schImage.ImageUrl = Page.ClientScript.GetWebResourceUrl(typeof(ctlB),

"Search.gif");

How can i get embeded resource in design mode to instead of

GetWebResourceUrl method ?

"bruce barker" <nospam@nospam.com>wrote in message

Quote

simple, your CreateChildControls references Page before it has been set.

your control should handle being created and its properties set before

being added to the Pages control collection. to work in a designer it

should handle nopage and no request.

defer references to other controls (like the page) until prerender or

render.

-- bruce (sqlwork.com)

Brook wrote:

>

>In webform.aspx: <cc:ctlB ID="ctl1" runat="server" Width="200px" />

>

>If set value to width property, I will get a error that say ctlB.Page is

>null. This control will be fine with no width property, why?

>

>Could anybody help me ? thanks

>

>

>

>*ctlA.cs*

>*----------------------------*

>[

>AspNetHostingPermission(SecurityAction.Demand, Level =

>AspNetHostingPermissionLevel.Minimal),

>AspNetHostingPermission(SecurityAction.InheritanceDemand, Level =

>AspNetHostingPermissionLevel.Minimal),

>DefaultProperty("Text"),

>ValidationProperty("Text"),

>ToolboxData("<{0}:ctlA runat=\"server\"></{0}:ctlA>")

>]

>public class ctlA : WebControl, INamingContainer

>{

>protected TextBox _textBox;

>protected HiddenField _hiddenBox;

>

>[Bindable(false), DefaultValue(""),

>TypeConverter(typeof(UnitConverter))]

>public override Unit Width

>{

>get

>{

>EnsureChildControls();

>return this._textBox.Width;

>}

>set

>{

>EnsureChildControls();

>this._textBox.Width = value;

>}

>}

>

>public override bool EnableViewState

>{

>get

>{

>EnsureChildControls();

>return this._textBox.EnableViewState;

>}

>set

>{

>EnsureChildControls();

>this._textBox.EnableViewState = value;

>this._hiddenBox.EnableViewState = value;

>this.EnableViewState = value;

>}

>}

>

>protected override void CreateChildControls()

>{

>this._textBox = new TextBox();

>this._textBox.ID = "Name";

>this._textBox.ReadOnly = this.ReadOnly;

>this._hiddenBox = new HiddenField();

>this._hiddenBox.ID = "Value";

>

>this.Controls.Add(this._textBox);

>this.Controls.Add(this._hiddenBox);

>}

>

>protected override void Render(HtmlTextWriter writer)

>{

>EnsureChildControls();

>base.Render(writer);

>}

>

>public override ControlCollection Controls

>{

>get

>{

>EnsureChildControls();

>return base.Controls;

>}

>}

>

>public ctlA()

>: base(HtmlTextWriterTag.Span)

>{

>}

>}

>------------------------------------------------------------------------

>*ctlB.cs*

>*------------------------------*

>

>[ToolboxData("<{0}:ctlB runat=\"server\"></{0}:ctlB>")]

>public class ctlB : ctlA

>{

>internal Image _schImage;

>

>public ctlB()

>: base()

>{

>}

>

>protected override void CreateChildControls()

>{

>base.CreateChildControls();

>

>this._schImage = new Image();

>this._schImage.ID = "imgButton";

>this._schImage.Attributes["align"] = "absmiddle";

>

>this._schImage.Attributes["onclick"] =

>String.Format("__OpenDialog('{0}', null, {1}, {2}, '{3}', '{4}', {5});",

>Page.ResolveUrl(this.DialogPagePath),

>this.DialogWidth.ToString(), this.DialogHeight.ToString(),

>this._textBox.ClientID, this._hiddenBox.ClientID, (this.DialogMode ==

>DialogMode.Model) ? "true" : "false");

>

>this.Controls.Add(_schImage);

>}

>

>protected override void OnPreRender(EventArgs e)

>{

>base.OnPreRender(e);

>

>this.Page.ClientScript.RegisterClientScriptResource(this.GetType(),

>"OpenDialog.js");

>}

>

>public override ControlCollection Controls

>{

>get

>{

>EnsureChildControls();

>return base.Controls;

>}

>}

>}

>