Dynamically Find Control

[rsdev]

Hi,

Can't get my head round this one!

I have incrementally named PlaceHolders and I want to dynamically load a control into each one. All fine if I strongly type the holder name. But how do I reference the holder name dynamically.

Here's what I have;

List<PageCompData> compType = PageCompData.GetCompType(pageId);
            int compLength = compType.Count;
            for (int i = 0; i < compLength; i++)
            {
                string compPath = "~/CMS/_admin/_components/" + compType[i].ComponentType + ".ascx";
                Control compControl = Page.LoadControl(compPath);
                (PlaceHolder)FindControl("PlaceHolder" + i).Controls.Add(compControl);
            }

Thanks.

[Plater]

Does that work?

.FindControl() only checks imediate children by default.
So for example, if you have a form, with a groupbox in it and then have 2 textboxes inside that groupbox:
myForm
mygroupbox
mytextbox1
mytextbox2

doing myForm.FindControl("mytextbox1"); will not work, you would need to do
mygroupbox.FindControl("mytextbox1"); to have it return the obbject.

Now, .FindControl() is overloaded to take a second parameter that will tell it to search the children of it's children, so with that 2nd parameter you could search in myForm for mytextbox1 and have it work.

[rsdev]

Hi Plater,

Thanks for your reply!

No it's not working. Findcontrol is the wrong call. I'll explain further.

I want to a list of control dynamically to my placeholders. The placeholder id's are PlaceHolder1, PlaceHolder2 ... etc. So I can loop through database results and add User Controls to the placeholders depending on the results. I usually script client-side Javascript/Actionscript and can't undertsand how to dynamically set/get the PlaceHolder id so I can add the control.

Any ideas?

Really struggling with this.

[Plater]

So you want to do this clientside and not in the backend code?

[rsdev]

Nope! Just trying to explain my ignorance.

How do I make this work;

PlaceHolder plcName = "PlaceHolder"+i;
plcName.Controls.Add(compControl);

Thanks

[Plater]

You can use FindControl to get object references to your placeholders.
Then create and add new controls to it.
For sake of argument:

PlaceHolder p = myowningcontrol.FindControl("PlaceHolder"+i.ToString());
//should check for null
//p.Controls.Clear();//uncomment this class to clear out any previous controls in there?
Label myl1=new Label();
myl1.ID=newUniqueID;//fix this to a unique ID somehow
myl1.text=displayDataFromDataBase1;//
p.Controlls.Add(myl1);
 
Label myl2=new Label();
myl2.ID=newUniqueID;//fix this to a unique ID somehow
myl2.text=displayDataFromDataBase2;//
p.Controlls.Add(myl2);
 

[rsdev]

Thanks again!

I am very close now except I don't have an ownercontrol. So I tried this;

PlaceHolder plcName = (PlaceHolder)Page.FindControl("PlaceHolderName"+i.ToString());
                plcName.Controls.Add(compControl);

But I get an error?

[rsdev]

Actually I've managed to make his work.

PlaceHolder plcName = (PlaceHolder)this.Master.FindControl("MainContent").FindControl("PlaceHolderName0);
plcName.Controls.Add(compControl);

But this doesn't

PlaceHolder plcName = (PlaceHolder)this.Master.FindControl("MainContent").FindControl("PlaceHolderName"+i.ToString());
plcName.Controls.Add(compControl);

I don't undertsand?!

[rsdev]

Okay even this works.

PlaceHolder plcName = (PlaceHolder)this.Master.FindControl("MainContent").FindControl("PlaceHolderName" + 0.ToString());

So why doesn't it recognise i as the int 0?

Sorry to bug you.

[rsdev]

I'm missing PLACEHOLDER. What an idiot. Thanks for your help. You did help me to solve this.

[Plater]

Do you need to search for MainContent or even placeholder at all?
That code you posted seem liks you coulda just done:
PlaceHolderName0.Controlls.Add(<whatever>);

Can't you just do

//the "i" was because you said you wanted to itterate through them.
PlaceHolder plcName = (PlaceHolder)MainContent.FindControl("PlaceHolderName"+i.ToString());
plcName.Add(<whatever>);
 

[rsdev]

Sorry I think I have confused you. The problem is solved thanks to your earlier post.

I am using masterpages so I needed to first find MainContent content holder. Then I loop through using i interger and add user controls to all the placeholders. Works well. Here's the final code;

 List<PageCompData> compType = PageCompData.GetCompType(pageIDS.Title);
            int compLength = compType.Count;
            int i=0;
            while(i<compLength)
            {
                string compPath = "~/CMS/_admin/_components/" + compType[i].ComponentType + ".ascx";
                Control compControl = Page.LoadControl(compPath);
                PlaceHolder plcName = (PlaceHolder)this.Master.FindControl("MainContent").FindControl("PlaceHolderName"+i.ToString());
                if (plcName == null)
                {
                    plcName = (PlaceHolder)this.Master.FindControl("RightColumn").FindControl("PlaceHolderName" + i.ToString());
                }
                plcName.Controls.Add(compControl);
                i++;
            }

Thanks again for your help:)