c# - Changing the color of a custom control -

i trying set background color of custom button. build button html overriding render method. expose attributes through customer overridden attribute methods , set capabilities. allows change parts of custom button after compiling.

i want change color of buttons div or table (i dont care which). how can this?

the button has table - how can programmatically grab table given know name ;buttontable.findcontrol not working, 'not set instance of object' error.

    panel buttonpnl = new panel(); //declare , init here in case need changing background color @ code compile , not run time     system.web.ui.webcontrols.image logoimg;     system.web.ui.webcontrols.image errorimg;     textbox maintexttb;     label subtextlbl;      protected override void createchildcontrols()     {         controls.clear();          //init controls         //buttonpnl.width = unit.pixel(200);         //buttonpnl.height = unit.pixel(150);         buttonpnl.id = "buttonpnl";          logoimg = new system.web.ui.webcontrols.image();         logoimg.id = "logoimg";         logoimg.width = unit.pixel(75);         logoimg.height = unit.pixel(75);          errorimg = new system.web.ui.webcontrols.image();         errorimg.id = "errorimg";         errorimg.width = unit.pixel(50);         errorimg.height = unit.pixel(50);          maintexttb = new textbox();         maintexttb.id = "maintexttb";         maintexttb.text = "changed";         maintexttb.font.size = 20;         maintexttb.width = unit.pixel(180);           subtextlbl = new label();         subtextlbl.id = "subtextlbl";         subtextlbl.text = "sub text";         subtextlbl.font.size = 12;          //add controls parent control         this.controls.add(logoimg);         this.controls.add(errorimg);         this.controls.add(maintexttb);         this.controls.add(subtextlbl);         this.controls.add(buttonpnl);     }      protected override void render(htmltextwriter writer)     {         //render controls         buttonpnl.rendercontrol(writer);         addattributestorender(writer);         writer.renderbegintag(htmltextwritertag.div); //table start tag         writer.addattribute(htmltextwriterattribute.cellpadding, "5");         writer.addattribute(htmltextwriterattribute.width, "200");         writer.addattribute(htmltextwriterattribute.id, "buttontable");         writer.renderbegintag(htmltextwritertag.table); //table start tag         writer.renderbegintag(htmltextwritertag.tr); //row start tag         writer.renderbegintag(htmltextwritertag.td); // cell start tag         logoimg.rendercontrol(writer); //add logo image         writer.renderendtag(); //cell end tag         writer.renderbegintag(htmltextwritertag.td); //cell start tag         errorimg.rendercontrol(writer); //add error image         writer.renderendtag(); //cell end tag         writer.renderendtag(); //row end tag         writer.renderbegintag(htmltextwritertag.tr); //row start tag         writer.addattribute(htmltextwriterattribute.width, "100%"); //make sure row width 100% of parent         writer.addattribute(htmltextwriterattribute.colspan, "2"); //make sure row spans 2 cells         writer.renderbegintag(htmltextwritertag.td); //cell start tag         maintexttb.rendercontrol(writer); //add main text box         writer.renderendtag(); //cell end tag         writer.renderendtag(); //row end tag         writer.addattribute(htmltextwriterattribute.align, "right"); //make sure row width 100% of parent         writer.renderbegintag(htmltextwritertag.tr); //row start tag         writer.addattribute(htmltextwriterattribute.width, "100%"); //make sure row width 100% of parent         writer.addattribute(htmltextwriterattribute.colspan, "2"); //make sure row spans 2 cells         writer.renderbegintag(htmltextwritertag.td); //cell start tag         subtextlbl.rendercontrol(writer); //add sub label         writer.renderendtag();//cell end tag         writer.renderendtag(); //row end tag         writer.renderendtag(); //table end tag         writer.renderendtag(); //div end tag     }      [category("appearance")]     [description("gets or sets panel colour")]     public color timbusbuttoncolour     {                                  {             ensurechildcontrols();             table buttontbl = (table)this.findcontrol("buttontable");             //return buttonpnl.backcolor;             return buttontbl.backcolor;         }          set         {             if (value != null)             {                 table buttontbl = (table)this.findcontrol("buttontable");                 //buttonpnl.backcolor = color.fromargb(value.r, value.g, value.b);                 buttontbl.backcolor = color.fromargb(value.r, value.g, value.b);             }         }     } 

resulting html pages source code

</div><div id="button1">     <table cellpadding="5" width="200" id="buttontable">         <tr>             <td><img id="button1_logoimg" src="" style="height:75px;width:75px;" /></td><td><img id="button1_errorimg" src="" style="height:50px;width:50px;" /></td>         </tr><tr>             <td width="100%" colspan="2"><input name="button1$maintexttb" type="text" value="changed" id="button1_maintexttb" style="font-size:20pt;width:180px;" /></td>         </tr><tr align="right">             <td width="100%" colspan="2"><span id="button1_subtextlbl" style="font-size:12pt;">sub text</span></td>         </tr>     </table> </div> 

you should use function similar this:

public static control findcontrolrecursive(control ctl, string id) {     if (!ctl.hascontrols())         return null;     control res = null;     foreach(control c in ctl.controls) {         if (c.id == id) {             res = c;             break;         } else {             res = findcontrolrecursive(c, id);             if (res != null)                 break;         }     }     return res; } 

in way:

table buttontbl = (table)findcontrolrecursive(this.page, "buttontable"); 

and find control sure.