Accessing parent properties in UserControls from different aspx page

Question

There is a aspx page which makes use of UserControl as follows.

Page1.aspx.cs

public class Page1
{
  public string Code {get;set;}
 ....

}

In the Page1.aspx a user control called "UsrControl"

<@Register TagPrefix="Usr" NameSpace="UsrControl">

I have the following code in UsrControl.

 public class UsrControl : Label
    {
      private Page1 _page1;
      
     protected override void OnInit(EventArgs e)
      {
        _page1 = (Page1)Page;
        string test = _page1.Code;
      }
.....
    }

In the usercontrol , the parent page is harcoded and from there the property of parent page (Page1) is being used .

Now the thing is I have one more aspx page Page2 which has same set of properties as Page1(Code) needed to invoke "UsrControl"

How can I refactor "UsrControl" to have the capability of accepting Page1 and Page2 and execute the code ? Should reflection be used?

score 1 · Answer 1 · answered Apr 05 '23 at 12:03

It would be easier to turn it around. Set the Code value from the page to the UserControl instead of getting it from the Page.

So in your UserControl add a property Code

public string Code { get; set; }

Then you can set that property from the aspx page of the parent.

<Usr:WebUserControl1 ID="WebUserControl1" runat="server" Code='<%# Code %>' />

And then call DataBind(); in Page_Load of the parent page.

public string Code { get; set; }

protected void Page_Load(object sender, EventArgs e)
{
    Code = "This is a test.";

    DataBind();
}

You can also add the UserControl programatically on the parent page and set Code from there.

public WebUserControl1 UsrControl { get; set; }
public string Code { get; set; }

protected void Page_Load(object sender, EventArgs e)
{
    Code = "This is a test.";

    UsrControl = (WebUserControl1)LoadControl("~/WebUserControl1.ascx");
    UsrControl.Code = Code;
    PlaceHolder1.Controls.Add(UsrControl);
}

score 1 · Answer 2 · answered Apr 05 '23 at 12:04

Just make an interface that shapes your data provider

public class IPageDataProvider
{
  string Code {get;set;}
}

and implement this interface in both your pages

public class Page1 : IPageDataProvider
{
  public string Code {get;set;}
  ....

}

public class Page2 : IPageDataProvider
{
  public string Code {get;set;}
  ....

}

After that, refactor your user control

public class UsrControl : Label
{
  private IPageDataProvider _pageDataProvider;
  
  protected override void OnInit(EventArgs e)
  {
    this._pageDataProvider = this.Page as IPageDataProvider;
    if ( this._pageDataProvider != null )
    {
      string test = this._pageDataProvider.Code;
    }
    else
    {
      // parent page doesn't implement the interface
    }
  }
}

Thanks but I am not allowed to introduce a interface for Page1 to implement. — user2630764, Apr 05 '23 at 12:26

Accessing parent properties in UserControls from different aspx page

2 Answers2