自定义服务器控件(转)

最新推荐文章于 2025-12-02 21:41:05 发布

最新推荐文章于 2025-12-02 21:41:05 发布 · 143 阅读

文章标签：

#ui

本文介绍两个 ASP.NET 自定义控件示例：MailLink 和 VacationHome。MailLink 控件用于创建电子邮件链接，而 VacationHome 控件则用于显示带有模板的复合控件，可以自定义显示的标题和描述。

示例代码：

// MailLink.cs
using System;
using System.ComponentModel;
using System.Security;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Samples.AspNet.CS.Controls
{
    [
    AspNetHostingPermission(SecurityAction.Demand,
        Level = AspNetHostingPermissionLevel.Minimal),
    AspNetHostingPermission(SecurityAction.InheritanceDemand, 
        Level=AspNetHostingPermissionLevel.Minimal),
    DefaultProperty("Email"),
    ParseChildren(true, "Text"),
    ToolboxData("<{0}:MailLink runat=/"server/"> <!--{0}:MailLink-->")
    ]
    public class MailLink : WebControl
    {
        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description("The e-mail address.")
        ]
        public virtual string Email
        {
            get
            {
                string s = (string)ViewState["Email"];
                return (s == null) ? String.Empty : s;
            }
            set
            {
                ViewState["Email"] = value;
            }
        }

        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description("The text to display on the link."),
        Localizable(true),
        PersistenceMode(PersistenceMode.InnerDefaultProperty)
        ]
        public virtual string Text
        {
            get
            {
                string s = (string)ViewState["Text"];
                return (s == null) ? String.Empty : s;
            }
            set
            {
                ViewState["Text"] = value;
            }
        }

        protected override HtmlTextWriterTag TagKey
        {
            get
            {
                return HtmlTextWriterTag.A;
            }
        }

        protected override void AddAttributesToRender(
            HtmlTextWriter writer)
        {
            base.AddAttributesToRender(writer);
            writer.AddAttribute(HtmlTextWriterAttribute.Href, 
                "mailto:" + Email);
        }

        protected override void RenderContents(HtmlTextWriter writer)
        {
            if (Text == String.Empty)
            {
                Text = Email;
            }
            writer.WriteEncodedText(Text);
        }
    }
}
参考：

http://msdn2.microsoft.com/en-us/library/f820d25y.aspx

带模板的服务器控件
// VacationHome.cs
using System;
using System.ComponentModel;
using System.Drawing;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.Design;

namespace Samples.AspNet.CS.Controls
{
 [
 AspNetHostingPermission(SecurityAction.InheritanceDemand, 
 Level=AspNetHostingPermissionLevel.Minimal),
 AspNetHostingPermission(SecurityAction.Demand,
 Level = AspNetHostingPermissionLevel.Minimal),
 Designer(typeof(VacationHomeDesigner)),
 DefaultProperty("Title"),
 ToolboxData(
 "<{0}:VacationHome runat=/"server/"> <!--{0}:VacationHome-->"),
 ]
 public class VacationHome : CompositeControl
 {
 private ITemplate templateValue;
 private TemplateOwner ownerValue;

 [
 Bindable(true),
 Category("Data"),
 DefaultValue(""),
 Description("Caption")
 ]
 public virtual string Caption
 {
 get
 {
 string s = (string)ViewState["Caption"];
 return (s == null) ? String.Empty : s;
 }
 set
 {
 ViewState["Caption"] = value;
 }
 }

 [
 Browsable(false),
 DesignerSerializationVisibility(
 DesignerSerializationVisibility.Hidden)
 ]
 public TemplateOwner Owner
 {
 get
 {
 return ownerValue;
 }
 }

 [
 Browsable(false),
 PersistenceMode(PersistenceMode.InnerProperty),
 DefaultValue(typeof(ITemplate), ""),
 Description("Control template"),
 TemplateContainer(typeof(VacationHome))
 ]
 public virtual ITemplate Template
 {
 get
 {
 return templateValue;
 }
 set
 {
 templateValue = value;
 }
 }

 [
 Bindable(true),
 Category("Data"),
 DefaultValue(""),
 Description("Title"),
 Localizable(true)
 ]
 public virtual string Title
 {
 get
 {
 string s = (string)ViewState["Title"];
 return (s == null) ? String.Empty : s;
 }
 set
 {
 ViewState["Title"] = value;
 }
 }

 protected override void CreateChildControls()
 {
 Controls.Clear();
 ownerValue = new TemplateOwner();

 ITemplate temp = templateValue;
 if (temp == null)
 {
 temp = new DefaultTemplate();
 }

 temp.InstantiateIn(ownerValue);
 this.Controls.Add(ownerValue);
 }

 public override void DataBind()
 {
 CreateChildControls();
 ChildControlsCreated = true;
 base.DataBind();
 }

 [
 ToolboxItem(false)
 ]
 public class TemplateOwner : WebControl
 {
 }

 #region DefaultTemplate
 sealed class DefaultTemplate : ITemplate
 {
 void ITemplate.InstantiateIn(Control owner)
 {
 Label title = new Label();
 title.DataBinding += new EventHandler(title_DataBinding);

 LiteralControl linebreak = new LiteralControl("
");

 Label caption = new Label();
 caption.DataBinding 
 += new EventHandler(caption_DataBinding);

 owner.Controls.Add(title);
 owner.Controls.Add(linebreak);
 owner.Controls.Add(caption);

 void caption_DataBinding(object sender, EventArgs e)
 {
 Label source = (Label)sender;
 VacationHome container = 
 (VacationHome)(source.NamingContainer);
 source.Text = container.Caption;
 }

 void title_DataBinding(object sender, EventArgs e)
 {
 Label source = (Label)sender;
 VacationHome container = 
 (VacationHome)(source.NamingContainer);
 source.Text = container.Title;
 }
 }
 #endregion


 public class VacationHomeDesigner : ControlDesigner
 {

 public override void Initialize(IComponent Component)
 {
 base.Initialize(Component);
 SetViewFlags(ViewFlags.TemplateEditing, true);
 }

 public override string GetDesignTimeHtml()
 {
 return "This is design-time HTML";
 }

 public override TemplateGroupCollection TemplateGroups
 {
 get {
 TemplateGroupCollection collection = new TemplateGroupCollection();
 TemplateGroup group;
 TemplateDefinition template;
 VacationHome control;

 control = (VacationHome)Component;
 group = new TemplateGroup("Item");
 template = new TemplateDefinition(this, "Template", control, "Template", true);
 group.AddTemplateDefinition(template);
 collection.Add(group);
 return collection;
 }
 }
 }