Creating a Basic Control Designer

Question

I'm trying to follow the walk-through:

Walkthrough: Creating a Basic Control Designer for a Web Server Control

basically I have created a new website with asp.net razor 4

and added this code :

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Web.UI;
using System.Web.UI.Design;
using System.Web.UI.Design.WebControls;
using System.Web.UI.WebControls;

namespace Samples.AspNet.CS.Controls
{

    public class SimpleCompositeControl : CompositeControl
    {


    private String _prompt = "Please enter your date of birth: ";
public virtual String Prompt
{
    get
    {
        object o = ViewState["Prompt"];
        return (o == null) ? _prompt : (string)o;
    }
    set
    {
        ViewState["Prompt"] = value;
    }
}

public virtual DateTime DOB
{
    get
    {
        object o = ViewState["DOB"];
        return (o == null) ? DateTime.Now : (DateTime)o;
    }
    set
    {
        ViewState["DOB"] = value;
    }
}





protected override void CreateChildControls() 
{
    Label lab = new Label();

    lab.Text = Prompt;
    lab.ForeColor = System.Drawing.Color.Red;
    this.Controls.Add(lab);

    Literal lit = new Literal();
    lit.Text = "<br />";
    this.Controls.Add(lit);

    TextBox tb = new TextBox();
    tb.ID = "tb1";
    tb.Text = DOB.ToString();
    this.Controls.Add(tb);

    base.CreateChildControls();
}




[Designer(typeof(SimpleCompositeControlDesigner))]
public class SimpleCompositeControl : CompositeControl


public class SimpleCompositeControlDesigner : CompositeControlDesigner
{
    // Set this property to prevent the designer from being resized.
    public override bool AllowResize 
    {
        get { return false; }
    }
}



}

how come im getting the type or namespace design does not exist ?

Answer 1

You need to add an Assembly reference to your project. In your Solution Explorer right click on References -> Add Reference -> Assemblies -> Framework -> then check the box next to System.Web and hit Okay to add that DLL to your project.

Do the same for System.Design .

---

Edit : To do this for a website. When you added a .cs file to your website solution, visual studio probably prompted you to have this file moved to an App_Code folder, assuming you said yes, as you should. Then right click on that folder and click add reference to add System.Design as System.Web is by default included in websites.