deletecolumn.aspx.cs

wrox c#高级编程

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;

using SqlAdmin;

namespace SqlWebAdmin
{
    /// <summary>
    /// Summary description for DeleteColumn.
    /// </summary>
    public class DeleteColumn : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Label ColumnNameLabel;
        protected System.Web.UI.WebControls.Label TableNameLabel;
        protected System.Web.UI.WebControls.Button YesButton;
        protected System.Web.UI.WebControls.Button NoButton;


        public DeleteColumn()
        {
            Page.Init += new System.EventHandler(Page_Init);
        }

        private void Page_Load(object sender, System.EventArgs e)
        {
            HttpCookie cookie = Request.Cookies["WebDataAdministrator"];
            if (cookie == null)
                Response.Redirect("default.aspx?error=sessionexpired");


            TableNameLabel.Text = Server.HtmlEncode(Request["table"]);
            ColumnNameLabel.Text = Server.HtmlEncode(Request["column"]);
        }

        private void Page_Init(object sender, EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
        }

        #region Web Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {    
            this.YesButton.Click += new System.EventHandler(this.YesButton_Click);
            this.NoButton.Click += new System.EventHandler(this.NoButton_Click);
            this.Load += new System.EventHandler(this.Page_Load);
        }
        #endregion

        private void YesButton_Click(object sender, System.EventArgs e) {
            HttpCookie cookie = Request.Cookies["WebDataAdministrator"];
            if (cookie == null)
                Response.Redirect("default.aspx?error=sessionexpired");

            SqlServer server = new SqlServer(cookie.Values["server"], cookie.Values["username"], cookie.Values["password"]);

            server.Connect();

            SqlDatabase database = server.Databases[Request["database"]];
            if (database == null) {
                server.Disconnect();

                // Database doesn't exist - break out and go to error page
                Response.Redirect(String.Format("error.aspx?error={0}", 1000));
                return;
            }

            SqlTable table = database.Tables[Request["table"]];
            if (table == null) {
                server.Disconnect();

                // Table doesn't exist - break out and go to error page
                Response.Redirect(String.Format("error.aspx?error={0}", 1002));
                return;
            }

            if (table.Columns.Count == 1) {
                server.Disconnect();
                throw new Exception("Cannot delete last column from table. A table must contain at least one column.");
            }

            // Select column from table
            SqlColumn column = table.Columns[Request["column"]];
            if (column == null) {
                server.Disconnect();

                // Column doesn't exist - break out and go to error page
                Response.Redirect(String.Format("error.aspx?error={0}", 1003));
                return;
            }

            // Delete the sproc
            column.Remove();

            server.Disconnect();

            // Redirect to info page
            Response.Redirect(String.Format("columns.aspx?database={0}&table={1}", Server.UrlEncode(Request["database"]), Server.UrlEncode(Request["table"])));
        }

        private void NoButton_Click(object sender, System.EventArgs e) {
            // Redirect to info page
            Response.Redirect(String.Format("columns.aspx?database={0}&table={1}", Server.UrlEncode(Request["database"]), Server.UrlEncode(Request["table"])));
        }
    }
}