ASP.NET Web 部件的数据绑定控件实例

下列代码实例说明了如何创建一个继承自 WebPart 类的自定义数据绑定控件，该控件能够在 Web 部件应用程序中被使用。关于如何建立这个控件以及在 ASP.NET 应用程序中使用它的详细内容，请参考：［ASP.NET 实践：建立并运行 Web 部件的数据绑定控件实例］。

实例

using System;

using System.Collections;

using System.ComponentModel;

using System.Drawing;

using System.Security.Permissions;

using System.Web;

using System.Web.Configuration;

using System.Data.Sql;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;



namespace Samples.AspNet.CS.Controls

{

  [AspNetHostingPermission(SecurityAction.Demand,

    Level = AspNetHostingPermissionLevel.Minimal)]

  [AspNetHostingPermission(SecurityAction.InheritanceDemand,

    Level = AspNetHostingPermissionLevel.Minimal)]

  public class SmallGridWebPart : WebPart

  {

    private String connString;



    // Use predefined strings for commands in the data source.

    private const string selectStmt = @"Select * from [Customers]";

    private const string deleteCmd = @"DELETE FROM [Customers] " +

      @"WHERE [CustomerID] = @CustomerID";

    private const string insertCmd = @"INSERT INTO [Customers] " +

      @"([CustomerID], [CompanyName], [ContactName], " +

      @"[Phone]) VALUES (@CustomerID, @CompanyName, " +

      @"@ContactName, @Phone)";

    private const string updateCmd = @"UPDATE [Customers] SET " +

      @"[CompanyName] = @CompanyName, [ContactName] = @ContactName, " +

      @"[Phone] = @Phone WHERE [CustomerID] = @CustomerID";





    public SmallGridWebPart()

    {

       ExportMode = WebPartExportMode.All;

    }



    // 这个重载防止用户关闭控件。

    public override bool AllowClose

    {

      get

      {

        return false;

      }

      // 没有实现 set 访问器。我们保留它是因为基类中包含这个属性，但是我们需要防止用户关闭控件以及开发者对该属性的更新。

      set { ; }

    }



    // 允许页面开发者设置连接串。

    public String ConnectionString

    {

      get { return connString; }

      set { connString = value; }

    }



    protected override void CreateChildControls()

    {

      Controls.Clear();



      // 创建 SqlDataSource 控件。

      SqlDataSource ds = new SqlDataSource(this.ConnectionString, selectStmt);

      ds.ID = "dsCustomers";

      ds.DataSourceMode = SqlDataSourceMode.DataSet;

      ds.InsertCommandType = SqlDataSourceCommandType.Text;

      ds.InsertCommand = insertCmd;

      ds.UpdateCommandType = SqlDataSourceCommandType.Text;

      ds.UpdateCommand = updateCmd;

      ds.DeleteCommandType = SqlDataSourceCommandType.Text;

      ds.DeleteCommand = deleteCmd;

      ParameterCollection deleteParams = new ParameterCollection();

      deleteParams.Add(BuildParam("CustomerID", TypeCode.String));

      ParameterCollection insertParams = new ParameterCollection();

      insertParams.Add(BuildParam("CustomerID", TypeCode.String));

      insertParams.Add(BuildParam("CompanyName", TypeCode.String));

      insertParams.Add(BuildParam("ContactName", TypeCode.String));

      insertParams.Add(BuildParam("Phone", TypeCode.String));

      ParameterCollection updateParams = new ParameterCollection();

      updateParams.Add(BuildParam("CustomerID", TypeCode.String));

      updateParams.Add(BuildParam("CompanyName", TypeCode.String));

      updateParams.Add(BuildParam("ContactName", TypeCode.String));

      updateParams.Add(BuildParam("Phone", TypeCode.String));



      this.Controls.Add(ds);



      // 创建 GridView 控件并把它绑定到 SqlDataSource。

      GridView grid = new GridView();

      grid.ID = "customerGrid";

      grid.Font.Size = 8;

      grid.AllowPaging = true;

      grid.AllowSorting = true;

      grid.AutoGenerateColumns = false;

      String[] fields = { "CustomerID" };

      grid.DataKeyNames = fields;

      grid.DataSourceID = "dsCustomers";

      CommandField controlButton = new CommandField();

      controlButton.ShowEditButton = true;

      controlButton.ShowSelectButton = true;

      grid.Columns.Add(controlButton);

      BoundField customerID = BuildBoundField("CustomerID");

      customerID.ReadOnly = true;

      grid.Columns.Add(customerID);

      grid.Columns.Add(BuildBoundField("CompanyName"));

      grid.Columns.Add(BuildBoundField("ContactName"));

      grid.Columns.Add(BuildBoundField("Phone"));



      this.Controls.Add(grid);



    }



    private Parameter BuildParam(String paramName, TypeCode dataTypeCode)

    {

      Parameter theParm = new Parameter(paramName, dataTypeCode);

      return theParm;

    }



    private BoundField BuildBoundField(String fieldName)

    {

      BoundField theField = new BoundField();

      theField.DataField = fieldName;

      theField.HeaderText = fieldName;

      theField.SortExpression = fieldName;

      return theField;

    }



  } 



}