Using Table control in a custom composite control. Control does not render properly in design time.

Discussion in 'ASP .Net Building Controls' started by jb_in_marietta@yahoo.com, Jul 1, 2003.

  1. Guest

    All,

    I have written a very simple custom composite control that includes a
    control of type System.Web.UI.WebControls.Table.

    The control renders fine in run time, but for some reason, it does not
    render properly in design time.

    In design time it renders something like this:

    [TestTableControl "TestTableControl1"]


    Could someone please explain why this control does not render in
    design time.
    (complete code is included below)

    Thanks in advance!!!

    --Jonathan

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


    using System;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.ComponentModel;
    using System.Collections;


    namespace StyleLibFunctions
    {
    #region TestTableControl

    [ToolboxData("<{0}:TestTableControl
    runat=server></{0}:TestTableControl>")]
    public class TestTableControl: WebControl
    {
    #region Variable Declaration

    private Table _table;
    private TableRow _tr;
    private TableCell _td;

    #endregion Variable Declaration

    #region Overridden Properties
    public override ControlCollection Controls
    {
    get
    {
    EnsureChildControls();
    return base.Controls;
    }
    }
    #endregion Overridden Properties

    #region Overridden Methods
    protected override void CreateChildControls ()
    {
    //clear controls
    Controls.Clear();

    //Create a Table object
    _table = new Table();
    _tr = new TableRow();
    _td = new TableCell();
    _td.Controls.Add(new LiteralControl("Cell Content"));

    _tr.Cells.Add(_td);
    _table.Rows.Add(_tr);

    //add table to control tree
    Controls.Add (_table);

    }
    protected override void Render(HtmlTextWriter writer)
    {
    _table.RenderControl(writer);
    }
    #endregion Overridden Methods
    }
    #endregion
    }
     
    , Jul 1, 2003
    #1
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  2. Teemu Keiski Guest

    Hi,

    you should implement composite control designer for the control and also
    generally implement INamingCotainer interface in the control.

    About designer implementation:

    a) Override Controls accessor to call EnsureChildControls before returning
    base class implementation (You have done this already)
    b) Write the designer and apply it for the control. Base logic is to call
    Control's (it is Component for the designer) Controls accessor to make sure
    child controls are created at the time when Control is rendered. This is
    done in overridden GetDesignTimeHtml method. In overridden Initialize method
    we just check that Control fulfills certain requirements. (You can also make
    the designer general by removing type checkings)

    Example:

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

    namespace StyleLibFunctions
    {
    #region TestTableControl
    [ToolboxData("<{0}:TestTableControl
    runat=server></{0}:TestTableControl>"),Designer(typeof(TestTableCompositeDes
    igner))
    ]
    public class TestTableControl: WebControl, INamingContainer
    {
    #region Variable Declaration
    private Table _table;
    private TableRow _tr;
    private TableCell _td;
    #endregion Variable Declaration
    #region Overridden Properties
    public override ControlCollection Controls
    {
    get
    {
    EnsureChildControls();
    return base.Controls;
    }
    }
    #endregion Overridden Properties
    #region Overridden Methods
    protected override void CreateChildControls ()
    {
    //clear controls
    Controls.Clear();
    //Create a Table object
    _table = new Table();
    _tr = new TableRow();
    _td = new TableCell();
    _td.Controls.Add(new LiteralControl("Cell Content"));
    _tr.Cells.Add(_td);
    _table.Rows.Add(_tr);
    //add table to control tree
    Controls.Add (_table);
    }
    protected override void Render(HtmlTextWriter writer)
    {
    _table.RenderControl(writer);
    }
    #endregion Overridden Methods
    }
    #endregion
    public class TestTableCompositeDesigner : ControlDesigner
    {
    public override void Initialize(IComponent component)
    {
    if(!(component is INamingContainer) && !(component is TestTableControl))
    {
    throw new ArgumentException("Component must be a TestTableControl and
    implement INamingContainer interface","component");
    }
    base.Initialize (component);
    }
    public override string GetDesignTimeHtml()
    {
    ControlCollection controls=((Control)Component).Controls;
    return base.GetDesignTimeHtml ();
    }
    }
    }

    --
    Teemu Keiski
    MCP,Designer/Developer
    Mansoft tietotekniikka Oy
    http://www.mansoft.fi

    ASP.NET Forums Moderator, www.asp.net
    AspAlliance Columnist, www.aspalliance.com

    Email:


    <> kirjoitti viestissä
    news:...
    > All,
    >
    > I have written a very simple custom composite control that includes a
    > control of type System.Web.UI.WebControls.Table.
    >
    > The control renders fine in run time, but for some reason, it does not
    > render properly in design time.
    >
    > In design time it renders something like this:
    >
    > [TestTableControl "TestTableControl1"]
    >
    >
    > Could someone please explain why this control does not render in
    > design time.
    > (complete code is included below)
    >
    > Thanks in advance!!!
    >
    > --Jonathan
    >
    > --------------------------------------------------------------------------

    ----
    >
    >
    > using System;
    > using System.Web;
    > using System.Web.UI;
    > using System.Web.UI.WebControls;
    > using System.ComponentModel;
    > using System.Collections;
    >
    >
    > namespace StyleLibFunctions
    > {
    > #region TestTableControl
    >
    > [ToolboxData("<{0}:TestTableControl
    > runat=server></{0}:TestTableControl>")]
    > public class TestTableControl: WebControl
    > {
    > #region Variable Declaration
    >
    > private Table _table;
    > private TableRow _tr;
    > private TableCell _td;
    >
    > #endregion Variable Declaration
    >
    > #region Overridden Properties
    > public override ControlCollection Controls
    > {
    > get
    > {
    > EnsureChildControls();
    > return base.Controls;
    > }
    > }
    > #endregion Overridden Properties
    >
    > #region Overridden Methods
    > protected override void CreateChildControls ()
    > {
    > //clear controls
    > Controls.Clear();
    >
    > //Create a Table object
    > _table = new Table();
    > _tr = new TableRow();
    > _td = new TableCell();
    > _td.Controls.Add(new LiteralControl("Cell Content"));
    >
    > _tr.Cells.Add(_td);
    > _table.Rows.Add(_tr);
    >
    > //add table to control tree
    > Controls.Add (_table);
    >
    > }
    > protected override void Render(HtmlTextWriter writer)
    > {
    > _table.RenderControl(writer);
    > }
    > #endregion Overridden Methods
    > }
    > #endregion
    > }
     
    Teemu Keiski, Jul 2, 2003
    #2
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