ASP.NET自定義控件開發系列（三）

時間 2019-12-18

標籤 asp.net asp 自定義控件開發系列欄目 ASP 简体版

原文原文鏈接

忽然發現不知道該寫點什麼了，記得當初作模版控件的時候遇到一個問題，這一篇文章就介紹一下模版控件的開發吧。
我想分兩塊來說：1、給現有的標準數據控件（如：Repeater ）建立動態模版，2、建立能夠使用模版的控件。

1、給現有的標準數據控件（如：Repeater ）建立模版

一、首先建立一個模版類：在這個模版中，咱們要顯示人員的姓名；而且人員的姓名是一個LinkButton,能夠點擊。

/// <summary>
/// Repeater模版
/// </summary>
internal class PersonTemplate : Control, ITemplate
{
string _Code;
string _Name;
public PersonTemplate(string Code, string Name)
{
_Code = Code;
_Name = Name;
}
void ITemplate.InstantiateIn(Control container)
{
LinkButton linkButton1 = new LinkButton();
linkButton1.ID = "lkbutton";
linkButton1.CommandName = "SelectPerson";
linkButton1.CausesValidation = false;
linkButton1.DataBinding += new EventHandler(this.LinkButtonBindData);
container.Controls.Add(new LiteralControl("<br/>"));
container.Controls.Add(linkButton1);
}
void LinkButtonBindData(object sender, System.EventArgs e)
{
LinkButton lButton1 = sender as LinkButton;
lButton1.CommandArgument = DataBinder.Eval(lButton1.NamingContainer, "DataItem." + _Code).ToString();
lButton1.Text = DataBinder.Eval(lButton1.NamingContainer, "DataItem." + _Name).ToString();
}
}

二、而後建立一個Panel,用於存放模版

internal class BasicPanel : Panel, INamingContainer
{
public BasicPanel()
{
}
}

三、控件部分：

[DefaultProperty("Text")]
[ToolboxData("<{0}:MyRepeater runat=server></{0}:MyRepeater>")]
[Designer(typeof(VeryCodes.Controls.Web.WebControlsDesigner))]
public class MyRepeater : CompositeControl
{
[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
public string Text
{
get
{
String s = (String)ViewState["Text"];
return ((s == null) ? String.Empty : s);
}
set
{
ViewState["Text"] = value;
}
}
private BasicPanel panel1;//搜索結果列表Panel
private Repeater rp;//搜索結果列表
private Label lb1;//選中項
/// <summary>
/// 綁定數據源
/// </summary>
[Bindable(true)]
[Browsable(false)]
public DataTable DataSource
{
get
{
if (ViewState[this.ClientID + "DataSource"] != null)
{
return (DataTable)ViewState[this.ClientID + "DataSource"];
}
else
{
return null;
}
}
set
{
ViewState[this.ClientID + "DataSource"] = value;
}
}
/// <summary>
/// 重寫Controls屬性
/// </summary>
public override ControlCollection Controls
{
get
{
EnsureChildControls();
return base.Controls;
}
}
/// <summary>
/// 重寫Render方法
/// </summary>
/// <param name="writer"></param>
protected override void Render(HtmlTextWriter output)
{
this.lb1.RenderControl(output);
this.panel1.RenderControl(output);
}
/// <summary>
/// 重寫OnPreRender方法
/// </summary>
/// <param name="e"></param>
protected override void OnPreRender(EventArgs e)
{
rp.DataSource = DataSource;
rp.DataBind();
}
/// <summary>
/// 重寫建立子控件
/// </summary>
protected override void CreateChildControls()
{
Controls.Clear();
CreateComponent();
SetComponentEvent();
}
/// <summary>
/// 添加子控件，並設置各個子控件的屬性
/// </summary>
private void CreateComponent()
{
lb1 = new Label();
panel1 = new BasicPanel();
rp = new Repeater();
lb1.ID = "lb1";
Controls.Add(lb1);
panel1.ID = "Panel1";
BasicPanel progressPanel = new BasicPanel();
if (rp.ItemTemplate == null)
{
rp.ItemTemplate = new PersonTemplate("Code", "Name");
}
rp.ItemTemplate.InstantiateIn(progressPanel);
rp.ID = "Repeater1";
panel1.Controls.Add(rp);
panel1.Controls.Add(progressPanel);
Controls.Add(panel1);
}
/// <summary>
/// 添加控件按鈕觸發事件
/// </summary>
private void SetComponentEvent()
{
this.rp.ItemCommand += new System.Web.UI.WebControls.RepeaterCommandEventHandler(this.lkbSelect_Click);
}
/// <summary>
/// 單擊模版內的按鈕觸發事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void lkbSelect_Click(object sender, RepeaterCommandEventArgs e)
{
if (e.Item.ItemIndex >= 0)
{
if (e.CommandName == "SelectPerson")
{
LinkButton lnkButton = e.Item.FindControl("lkbutton") as LinkButton;
lb1.Text = "選擇項是：" + lnkButton.Text;
}
}
}

MyRepeater這個控件就到此爲止了，須要在包含控件的頁面中綁定一個數據源給它，例如

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataTable dt = new DataTable();
dt.Columns.Add("Code");
dt.Columns.Add("Name");
DataRow dr = dt.NewRow();
dr[0] = "001";
dr[1] = "張三";
dt.Rows.Add(dr);
DataRow dr1 = dt.NewRow();
dr1[0] = "002";
dr1[1] = "李四";
dt.Rows.Add(dr1);
DataRow dr2 = dt.NewRow();
dr2[0] = "003";
dr2[1] = "王五";
dt.Rows.Add(dr2);
MyRepeater1.DataSource = dt;
}
}

2、建立能夠使用模版的控件
我發現要想作好一件事，真的很難。最近因疲於工做，不多有時間研究技術，很長時間寫不了多少。
我想這一部分就介紹一個最簡單的模版控件了，我實在太懶了，只是貼點代碼。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace VeryCodes.Controls.Web
{
[DefaultProperty("Text")]
[ToolboxData("<{0}:TemplateTest runat=server></{0}:TemplateTest>")]
public class TemplateTest : WebControl, INamingContainer//必須實現接口INamingContainer
{
private ITemplate _itemTemplate;
//屬性
[Browsable(false)]
[TemplateContainer(typeof(TemplateTest))]
[PersistenceMode(PersistenceMode.InnerProperty)]
public ITemplate ItemTemplate
{
get { return _itemTemplate; }
set { _itemTemplate = value; }
}
protected override void CreateChildControls()
{
_itemTemplate.InstantiateIn(this);//建立模版控件
}
}
}