ASP.NET实现在服务器端控制网页

Panel控件
• Panel是一个服务器端的Web表单控件，一
个Panel控件就是HTML网页上的一个矩形
区域，它是否可见可以在服务器端进行控
制。因此，首先，我们可以从将HTML代码
段放在一个Panel控件中，HTML代码段可
以由服务器端控件和客户端控件组成。一
旦我们将Panel控件的visibility属性设置为
“false”，则整个HTML代码段就成为不可见
的了

private void btnNext_Click(object sender, System.EventArgs e)
        {
            Panel mypanel;
            string panelname;

            panelname = "Panel" + Session["currentpage"];
            mypanel = (Panel)FindControl(panelname);
            mypanel.Visible = false;

            int currentpage = (int)Session["currentpage"];
            currentpage += 1;
            Session["currentpage"] = currentpage;
            panelname = "Panel" + Session["currentpage"];
            mypanel = (Panel)FindControl(panelname);
            mypanel.Visible =true;

        }

        private void btnPrev_Click(object sender, System.EventArgs e)
        {
            Panel mypanel;
            string panelname;
 
            panelname = "Panel" + Session["currentpage"];
            mypanel = (Panel)FindControl(panelname);
            mypanel.Visible = false;

            int currentpage = (int)Session["currentpage"];
            currentpage -= 1;
            Session["currentpage"] = currentpage;
            panelname = "Panel" + Session["currentpage"];
            mypanel = (Panel)FindControl(panelname);
            mypanel.Visible = true;

        }

服务器控件的动态添加
PlaceHolder ：
• 控件的容器！！
• 它使你可以将空容器控件放置到页内，
然后在运行时动态添加、移除或依次通
过子元素。该控件只呈现其子元素；它
不具有自己的基于HTML 的输出

private void Page_Load(object sender, System.EventArgs e)
        {
            // ÔÚ´Ë´¦·ÅÖÃÓû§´úÂëÒÔ³õʼ»¯Ò³Ãæ
            if ((ViewState["AddControl"]!= null) && ((bool)ViewState["AddControl"])) 
            {
                phMain.Controls.Clear(); 
                //Ìí¼Ó±êÇ©
                Label lb = new Label();
                lb.Text = "ÇëÑ¡ÔñÓû§ÐÕÃû!"+"<br>";
                phMain.Controls.Add(lb);
                DropDownList ddl = new DropDownList(); 
                ddl.ID="controlID"; 
                ddl.AutoPostBack = true;
                phMain.Controls.Add(ddl);
            }
            else
            {
                phMain.Controls.Clear(); 
                //Ìí¼Ó±êÇ©
                Label lb = new Label();
                lb.Text = "ÇëÑ¡ÔñÓû§ÐÕÃû!"+"<br>";
                phMain.Controls.Add(lb);
                DropDownList ddl = new DropDownList(); 
                ddl.ID="controlID"; 
                ddl.AutoPostBack = true;
                //phMain.Controls.Add(ddl);
                ddl.Width=200; 
                string strConn = ConfigurationSettings.AppSettings["DSN"];            
                string strSQL = "Select Username from tbUserInfo";//Select²éѯÓï¾ä
                SqlConnection myCn = new SqlConnection(strConn);            
                try
                {
                    myCn.Open();
                    SqlDataAdapter sda = new SqlDataAdapter(strSQL,myCn);
                    DataSet ds = new DataSet("ds");
                    sda.Fill(ds,"Item");
                    ddl.DataSource = ds.Tables["Item"].DefaultView;
                    ddl.DataTextField = "UserName";
                    ddl.DataBind();
                    phMain.Controls.Add(ddl);
            
                }
                catch(System.Data.SqlClient.SqlException ee)
                {                
                    throw new Exception(ee.Message);
                }
                finally
                {
                    myCn.Close();
                }
                ViewState["AddControl"] = true; 


            }
        }

服务器控件的动态添加
Panel ：
• Panel 控件是其他控件的容器。
• 如果打算以编程方式生成多个控件或者
打算隐藏/显示一组控件，此控件尤其有
用。

private void Page_Load(object sender, System.EventArgs e)
        {
            CreateDataGrid();
        }
        private void CreateDataGrid()
        {

            Panel pnMain = new Panel();
            pnMain.Style["Position"]="Absolute";
            pnMain.Style["Top"]="30px";
            pnMain.Style["Left"]="100px";
            pnMain.Style["Width"]="500px";
            pnMain.Style["Height"]="300px";
            pnMain.Style["OVERFLOW"]="auto";//PanelµÄ´óС²»ËæDataGridµÄ´óС·¢Éú±ä»¯
            this.Controls.Add(pnMain);        
            
            DataGrid myDataGrid=new DataGrid();

            BoundColumn s1=new BoundColumn();
            s1.DataField="EmployeeID";
            s1.HeaderText="¹ÍÔ±ID";
            myDataGrid.Columns.Add(s1);


            BoundColumn s2=new BoundColumn();
            s2.DataField="LastName";
            s2.HeaderText="ÐÕ";
            myDataGrid.Columns.Add(s2);


            BoundColumn s3=new BoundColumn();
            s3.DataField="FirstName";
            s3.HeaderText="Ãû";
            myDataGrid.Columns.Add(s3);


            BoundColumn s4=new BoundColumn();
            s4.DataField="Title";
            s4.HeaderText="±êÌâ";
            myDataGrid.Columns.Add(s4);


            BoundColumn s5=new BoundColumn();
            s5.DataField="BirthDate";
            s5.HeaderText="ÉúÈÕ";
            myDataGrid.Columns.Add(s5);


            BoundColumn s6=new BoundColumn();
            s6.DataField="Address";
            s6.HeaderText="µØÖ·";
            myDataGrid.Columns.Add(s6);

            myDataGrid.Style["Position"]="Absolute";
            myDataGrid.Style["Left"]="0px";
            myDataGrid.Style["Top"]="0px";


            myDataGrid.BorderColor=Color.FromName("#DEBA84");
            myDataGrid.BackColor=Color.FromName("#DEBA84");
            myDataGrid.Style["BorderStyle"]="None";
            myDataGrid.Attributes.Add("BorderStyle","None");


            myDataGrid.CellPadding=3;
            myDataGrid.CellSpacing=2;
            myDataGrid.Attributes.Add("BorderWidth","1px");
            myDataGrid.PageSize=2;
            myDataGrid.AutoGenerateColumns=true;


            myDataGrid.SelectedItemStyle.Font.Bold=true;
            myDataGrid.SelectedItemStyle.ForeColor=Color.White;
            myDataGrid.SelectedItemStyle.BackColor=Color.FromName("#738A9C");


            myDataGrid.ItemStyle.ForeColor=Color.FromName("#8C4510");
            myDataGrid.ItemStyle.BackColor=Color.FromName("#FFF7E7");
            myDataGrid.ItemStyle.HorizontalAlign=HorizontalAlign.Center;

            myDataGrid.ItemStyle.Wrap=false;


            myDataGrid.HeaderStyle.Font.Bold=true;
            myDataGrid.HeaderStyle.ForeColor=Color.White;
            myDataGrid.HeaderStyle.BackColor=Color.FromName("#A55129");
            myDataGrid.HeaderStyle.HorizontalAlign=HorizontalAlign.Center;
            myDataGrid.HeaderStyle.Wrap=false;


            myDataGrid.AutoGenerateColumns=false;
            myDataGrid.HorizontalAlign=HorizontalAlign.Center;


            myDataGrid.PagerStyle.HorizontalAlign=HorizontalAlign.Center;
            myDataGrid.PagerStyle.Wrap=false;
            myDataGrid.Attributes.Add("style","word-break:keep-all;word-wrap:normal");


            pnMain.Controls.Add(myDataGrid);//°ÑDataGridÌí¼Óµ½PanelÖÐ


            SqlConnection thisConnection=new SqlConnection ("Data Source=(local);Initial Catalog=Northwind;UID=sa;PWD=111");
            SqlCommand thisCommand=thisConnection.CreateCommand ();
            try
            {
                thisConnection.Open ();
            }
            catch(Exception ex)
            {
                thisConnection.Close ();
            }
            thisCommand.CommandText ="select * from employees";
            SqlDataReader sqlDataReader;
            sqlDataReader=thisCommand.ExecuteReader ();
            myDataGrid.DataSource =sqlDataReader;


            myDataGrid.DataBind();
            sqlDataReader.Close();
        }

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace ServerSideControl
{
    /**//// <summary>
    /// WebForm1 µÄժҪ˵Ã÷¡£
    /// </summary>
    public class WebForm1 : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Button btnAdd;
        protected System.Web.UI.WebControls.Button btnDel;
        protected System.Web.UI.WebControls.Panel pnMain;
    
        private void Page_Load(object sender, System.EventArgs e)
        {
            if (!IsPostBack)
                Session["count"] = 1;
            ShowControl();
        }

        Web Form Designer generated code#region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN£º¸Ãµ÷ÓÃÊÇ ASP.NET Web ´°ÌåÉè¼ÆÆ÷Ëù±ØÐèµÄ¡£
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /**//// <summary>
        /// Éè¼ÆÆ÷Ö§³ÖËùÐèµÄ·½·¨ - ²»ÒªÊ¹ÓôúÂë±à¼­Æ÷ÐÞ¸Ä
        /// ´Ë·½·¨µÄÄÚÈÝ¡£
        /// </summary>
        private void InitializeComponent()
        {    
            this.btnAdd.Click += new System.EventHandler(this.btnAdd_Click);
            this.btnDel.Click += new System.EventHandler(this.btnDel_Click);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void btnAdd_Click(object sender, System.EventArgs e)
        {
            Session["count"] = (int)Session["count"] +1; 
            ShowControl();
        }

        private void btnDel_Click(object sender, System.EventArgs e)
        {
            Session["count"] = (int)Session["count"] -1; 
            ShowControl();
            
        }
        private void ShowControl()
        {
            textBoxArray tba = new textBoxArray(pnMain);
            int nCount = (int)Session["count"];
            pnMain.Controls.Clear();
            for(int i=1;i<=nCount;i++)
                tba.addNewTextBox();
        }
    }
    //************************** 
    //ÀàtextBoxArrayʵÏÖÁ˶¯Ì¬Ôö¼ÓºÍɾ³ý 
    //textBoxµÄ¹¦ÄÜ 
    //************************** 
    public class textBoxArray:System.Collections.CollectionBase 
    { 
        private readonly System.Web.UI.Control HostPage;
        //¹¹Ô캯Êý 
        public textBoxArray(System.Web.UI.Control Host) 
        { 
            HostPage=Host; 
        } 
        //addNewTextBox·½·¨Ìí¼ÓÒ»¸ötextbox¿Ø¼þ 
        public void addNewTextBox() 
        { 
            //this.List.Add(this.Count.ToString());

            //½¨Ò»¸öеÄtextboxʵÀý. 
            TextBox aTextBox=new TextBox(); 
            //½«ÆäÌí¼Óµ½¼¯ºÏµÄÄÚ²¿Áбí 
            this.List.Add(aTextBox); 
            //½«TextBoxÌí¼Óµ½ÓÉHostForm×Ö¶ÎÒýÓõĴ°ÌåµÄ¼¯ºÏÁбíÖР
            HostPage.Controls.Add(aTextBox); 
            //ÉèÖóõʼÊôÐÔ 
            aTextBox.Style["Left"]=Convert.ToString((Count-1)*130+70); 
            aTextBox.Style["Top"] = Convert.ToString(160);
            aTextBox.Width=120; 
            aTextBox.BorderStyle=BorderStyle.Outset;
            aTextBox.ID=this.Count.ToString(); 
            //³õʼֵ 
            aTextBox.Text="TextBoxʾÀý"; 
            aTextBox.ForeColor=System.Drawing.Color.Blue; 
            
            
        } 
        //´´½¨Ë÷Òý 
        public TextBox this [int index] 
        { 
            get 
            { 
                return (TextBox)this.List[index]; 
            } 
        } 
        //Remove·½·¨ÓÃÀ´É¾³ý¿Ø¼þ 
        public void Remove() 
        { 
            if(this.Count>0) 
            { 
                HostPage.Controls.Remove (this[this.Count -1]); 
                this.List.RemoveAt(this.Count-1); 
            } 
        } 
    }

}

        private void Page_Load(object sender, System.EventArgs e)
        {
            Button Button1 = new Button();
            Button1.CommandArgument = "b1";
            Button1.Text = "Btn1";
            Button1.Command += new CommandEventHandler(this.OnButton); 
            PlaceHolder1.Controls.Add(Button1); 
            Button Button2 = new Button();
            Button2.CommandArgument = "b2";
            Button2.Text = "Btn2";
            Button2.Command += new CommandEventHandler(this.OnButton); 
            PlaceHolder1.Controls.Add(Button2); 


            Control c3 = ParseControl("<asp:Button id='Button3' text='Btn3' commandname='Btn' commandargument='b3' runat='server' />"); 
            Control c4 = ParseControl("<asp:Button id='Button4' text='Btn4' commandname='Btn' commandargument='b4' runat='server' />"); 
            PlaceHolder1.Controls.Add(c3); 
            PlaceHolder1.Controls.Add(c4); 
            Button myBut = (Button)Page.FindControl("Button3"); 
            myBut.Command += new CommandEventHandler(this.OnButton); 
            Button myBut2 = (Button)Page.FindControl("Button4"); 
            myBut2.Command += new CommandEventHandler(this.OnButton); 

        }
        public void OnButton(Object Sender, CommandEventArgs e) 
        { 
            switch (e.CommandArgument.ToString().ToLower()) 
            { 
                case "b1": 
                    Label1.Text = "Button 1"; 
                    break; 
                case "b2": 
                    Label1.Text = "Button 2"; 
                    break; 
                case "b3": 
                    Label1.Text = "Button 3"; 
                    break; 
                case "b4": 
                    Label1.Text = "Button 4"; 
                    break; 
            }; 
        } 

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace ServerSideControl
{
    /**//// <summary>
    /// AddInTable 的摘要说明。
    /// </summary>
    public class AddInTable : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Table Table1;
        protected System.Web.UI.WebControls.PlaceHolder PlaceHolder1;
        protected System.Web.UI.WebControls.Button btnAdd;
    
        private void Page_Load(object sender, System.EventArgs e)
        {
            if(ViewState["Count"]!=null) 
            { 
                for(int i=0;i<Convert.ToInt16(ViewState["Count"]);i++) 
                    AddTextBoxs(); 
                AddButton(); 
            } 

        }

        Web Form Designer generated code#region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN：该调用是 ASP.NET Web 窗体设计器所必需的。
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /**//// <summary>
        /// 设计器支持所需的方法 - 不要使用代码编辑器修改
        /// 此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {    
            this.btnAdd.Click += new System.EventHandler(this.btnAdd_Click);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void btnAdd_Click(object sender, System.EventArgs e)
        {
            AddTextBoxs(); 
            if(ViewState["Count"]==null)
                AddButton(); 
            ViewState["Count"]=Convert.ToInt16(ViewState["Count"])+1; 
        }
        private void AddTextBoxs() 
        { 
            TableRow tr=new TableRow(); 
            TableCell tc1=new TableCell(); 
            TextBox t=new TextBox(); 
            t.ID="tb"+Table1.Rows.Count; 
            tc1.Controls.Add(t); 
            TableCell tc2=new TableCell(); 
            DropDownList dpl=new DropDownList(); 
            dpl.ID="dpl"+Table1.Rows.Count; 
            for(int i=0;i<10;i++)dpl.Items.Add(i.ToString()); 
            tc2.Controls.Add(dpl); 
            tr.Cells.Add(tc1); 
            tr.Cells.Add(tc2); 
            Table1.Rows.Add(tr); 
        } 

        private void AddButton() 
        {         
            Button b=new Button(); 
            b.ID="btn"; 
            b.Text="显示"; 
            b.Click += new System.EventHandler(btn_Click); 
            PlaceHolder1.Controls.Add(b); 
        } 
        private void btn_Click(object sender, System.EventArgs e) 
        { 
            for(int i=0;i<Table1.Rows.Count;i++) 
            { 
                Response.Write(((TextBox)Table1.Rows[i].FindControl("tb"+i)).Text+((DropDownList)Table1.Rows[i].FindControl("dpl"+i)).SelectedItem.Value+"<br>"); 
            } 
        } 
    }
}

动态添加HTML控件
• 客户端事件，与服务端事件是不同的，
客户端事件在服务端看来就是一种显示效
果而已。
• 服务端程序认为为控件添加一个样式信
息，和添加一个客户端事件是一样的。

    private void Page_Load(object sender, System.EventArgs e)
        {
            btn.Attributes["onclick"]= "javascript:alert('¿Í»§¶Ëʼþ!!');";    

        }
private void InitializeComponent()
        {    
            this.btn.Click += new System.EventHandler(this.btn_Click);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void btn_Click(object sender, System.EventArgs e)
        {
            Response.Write("<DIV style='DISPLAY: inline; Z-INDEX: 102; LEFT: 227px; WIDTH: 210px; COLOR: green; FONT-STYLE: italic; POSITION: absolute; TOP: 126px; HEIGHT: 64px; FONT-VARIANT: normal' ms_positioning='FlowLayout'>ÕâÊÇ¿Í»§¶Ëhtml£¡</DIV>");

        }