溫故知新ASP.NET 2.0(C#)(8) - DataSourceControl

作者: webabcd 來源: 博客園發布時間: 2008-09-16 18:05 閱讀: 3160 次推薦: 0 原文鏈接 [收藏]

系列文章導航：

溫故知新ASP.NET 2.0(C#)(1) - MasterPage(母版頁)

溫故知新ASP.NET 2.0(C#)(2) - Themes(主題)

溫故知新ASP.NET 2.0(C#)(3) - SiteMap(站點地圖)

溫故知新ASP.NET 2.0(C#)(4) - 緩存&SqlCacheDependency

溫故知新ASP.NET 2.0(C#)(5) - Localization

溫故知新ASP.NET 2.0(C#)(8) - DataSourceControl

溫故知新ASP.NET 2.0(C#)(6) - Membership&RoleManager

溫故知新ASP.NET 2.0(C#)(7) - Profile

溫故知新ASP.NET 2.0(C#)(8) - DataSourceControl

介紹
　　在 ASP.NET 2.0 中有幾個新的數據源控件，例如，SqlDataSource、ObjectDataSource、XmlDataSource、AccessDataSource 和 SiteMapDataSource。它們全都可以用來從它們各自類型的數據源中檢索數據，并且可以綁定到各種數據綁定控件。數據源控件減少了為檢索和綁定數據甚至對數據進行排序、分頁或編輯而需要編寫的自定義代碼的數量。

　　其中 ObjectDataSource 控件可針對各種基礎數據存儲區（如 SQL 數據庫或 XML）啟用聲明性數據綁定模型。因為頁開發人員也常常將數據檢索（也可能包含業務邏輯）封裝在一個組件對象中，從而在呈現頁和數據提供程序之間引入另一個層。ObjectDataSource 控件允許開發人員使用此傳統的三層結構構造應用程序，同時仍然能夠利用 ASP.NET 中的聲明性數據綁定模型的易用性優點。

關鍵
　　1、在數據層創建強類型的DataSet和TableAdapter，TableAdapter查詢可以使用現有的存儲過程。注：直接把表或存儲過程拖進來會自動創建TableAdapter；

　　2、中間層的類用[System.ComponentModel.DataObject]聲明為數據組件，CRUD方法分別對應　　　　　　　[DataObjectMethod(DataObjectMethodType.Insert)]，[DataObjectMethod(DataObjectMethodType.Select)]，[DataObjectMethod(DataObjectMethodType.Update)]，[DataObjectMethod(DataObjectMethodType.Delete)] ；

　　3、web層使用ObjectDataSource展現數據，ObjectDataSource就相當于一個代理。ObjectDataSource只是查找具有匹配的參數名稱的方法，它不會使用參數的 Type 或 Size，而只是對參數的名稱進行匹配；

　　4、其它

　　·<asp:Parameter />有ConvertEmptyStringToNull屬性，默認是true。另外還有Direction屬性
　 ·注意<asp:BoundField />的這幾個屬性NullDisplayText，HtmlEncode，ApplyFormatInEditMode，InsertVisible，DataFormatString，ReadOnly
　　·DataKeyNames有多個值的話用“,”分隔，用<asp:ControlParameter />綁定的話給其加一個“PropertyName”屬性，值類似如下“SelectedDataKey.Values[0]”
　　·關于綁定：簡單屬性<%# custID %>；集合<asp:ListBox id="List1" datasource='<%# myArray %>' runat="server">；表達式<%# ( customer.FirstName + " " + customer.LastName ) %>；方法<%# GetBalance(custID) %>
　　·<%# Eval("field1") %> 和 <%# Bind("field1") %>，Eval是單向綁定，Bind是雙向邦定
　　·<asp:ObjectDataSource />有一個OldValuesParameterFormatString屬性一般不用，不過如果要處理樂觀并發之類的就會用到。當該屬性的值為“original_{0}”的時候“original_參數名”則為初始值
　　·還有一些如編程方式給參數賦值，錯誤處理，得到返回值之類的請看源碼

示例
相關存儲過程和數據層略；

單例模式的實現
App_Code/Singleton.cs

Code
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/**//// <summary>
/// Singleton 的摘要說明
/// </summary>
public class Singleton<T> where T : new()
{
    public static T Instance
    {
        get { return SingletonCreator.instance; }
    }

    class SingletonCreator
    {
        internal static readonly T instance = new T();
    }
}

中間層代碼
App_Code/Test.cs

Code
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

using TestDatabaseTableAdapters;
using System.ComponentModel;

/**//// <summary>
/// Test 的摘要說明
/// </summary>
[DataObject]
public class Test
{
    [DataObjectMethod(DataObjectMethodType.Select, true)]
    public TestDatabase.TestDataTable GetTest()
    {
        return Singleton<TestTableAdapter>.Instance.GetTest();
    }

    [DataObjectMethod(DataObjectMethodType.Select, false)]
    public TestDatabase.TestDataTable GetTestById(int id)
    {
        return Singleton<TestTableAdapter>.Instance.GetTestById(id);
    }

    [DataObjectMethod(DataObjectMethodType.Insert, true)]
    public int?[] InsertTest(int? parentId, string name, DateTime? publishTime, decimal? price, bool? isGood, out int? minId)
    {
        // 僅為說明如何做錯誤處理
        if (String.IsNullOrEmpty(name))
            throw new ArgumentException("參數不能是空", "name");

        int? id = null;
        int? count = null;
        minId = null;

        Singleton<TestTableAdapter>.Instance.InsertTest(parentId, name, publishTime, price, isGood, ref id, ref count, ref minId);
        return new int?[] { id, count };
    }

    [DataObjectMethod(DataObjectMethodType.Delete, true)]
    public int? DeleteTest(int id)
    {
        int? rowAffected;

        rowAffected = Singleton<TestTableAdapter>.Instance.DeleteTest(id);
        return rowAffected;
    }

    [DataObjectMethod(DataObjectMethodType.Update, true)]
    public int? UpdateTest(int? id, int? parentId, string name, DateTime? publishTime, decimal? price, bool? isGood)
    {
        int? rowAffected;

        rowAffected = Singleton<TestTableAdapter>.Instance.UpdateTest(id, parentId, name, publishTime, price, isGood);
        return rowAffected;
    }
}

DataSourceControl/Test.aspx

Code
<%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Test.aspx.cs"
    Inherits="DataSourceControl_Test" Title="數據源控件測試" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
    <p>
        <asp:Label ID="lblMsg" runat="server" ForeColor="red" />
    </p>
    <table cellpadding="6">
        <tr>
            <td valign="top">
                <asp:DetailsView ID="DetailsView1" runat="server" AllowPaging="True" AutoGenerateRows="False"
                    DataKeyNames="Id" DataSourceID="ObjectDataSource1" Height="50px" Width="125px" OnItemInserted="DetailsView1_ItemInserted">
                    <Fields>
                        <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" ReadOnly="True"
                            SortExpression="Id" />
                        <asp:BoundField DataField="ParentId" HeaderText="ParentId" SortExpression="ParentId" />
                        <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                        <asp:BoundField DataField="PublishTime" HeaderText="PublishTime" SortExpression="PublishTime"
                            InsertVisible="False" />
                        <asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" DataFormatString="{0:c}" HtmlEncode="False" />
                        <asp:CheckBoxField DataField="IsGood" HeaderText="IsGood" SortExpression="IsGood" />
                        <asp:CommandField ShowInsertButton="True" />
                    </Fields>
                </asp:DetailsView>
            </td>
            <td valign="top">
                <asp:DetailsView ID="DetailsView2" runat="server" Height="50px" Width="125px" AutoGenerateRows="False" DataKeyNames="Id" DataSourceID="ObjectDataSource2">
                    <Fields>
                        <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" ReadOnly="True"
                            SortExpression="Id" />
                        <asp:BoundField DataField="ParentId" HeaderText="ParentId" SortExpression="ParentId" />
                        <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                        <asp:BoundField DataField="PublishTime" HeaderText="PublishTime" SortExpression="PublishTime" />
                        <asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" DataFormatString="{0:c}" HtmlEncode="false" />
                        <asp:CheckBoxField DataField="IsGood" HeaderText="IsGood" SortExpression="IsGood" />
                    </Fields>
                </asp:DetailsView>
            </td>
        </tr>
    </table>
    <p>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Id"
            DataSourceID="ObjectDataSource1" AllowPaging="True" AllowSorting="True" OnRowUpdating="GridView1_RowUpdating">
            <Columns>
                <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" ShowSelectButton="True" />
                <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" ReadOnly="True"
                    SortExpression="Id" />
                <asp:BoundField DataField="ParentId" HeaderText="ParentId" SortExpression="ParentId"
                    NullDisplayText="我的值是NULL" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="PublishTime" HeaderText="PublishTime" SortExpression="PublishTime"
                    ReadOnly="true" />
                <asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" DataFormatString="{0:c}" HtmlEncode="false" ApplyFormatInEditMode="True" />
                <asp:CheckBoxField DataField="IsGood" HeaderText="IsGood" SortExpression="IsGood" />
            </Columns>
        </asp:GridView>
    </p>
    <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetTest"
        TypeName="Test" InsertMethod="InsertTest" DeleteMethod="DeleteTest" UpdateMethod="UpdateTest"
        OnInserting="ObjectDataSource1_Inserting" OnInserted="ObjectDataSource1_Inserted">
        <InsertParameters>
            <%--ConvertEmptyStringToNull屬性默認為true--%>
            <asp:Parameter Name="parentId" Type="Int32" ConvertEmptyStringToNull="true" />
            <asp:Parameter Name="name" Type="String" />
            <asp:Parameter Name="publishTime" Type="DateTime" />
            <asp:Parameter Name="price" Type="Decimal" />
            <asp:Parameter Name="isGood" Type="Boolean" />
            <asp:Parameter Direction="Output" Name="minId" Type="Int32" />
        </InsertParameters>
        <DeleteParameters>
            <asp:Parameter Name="id" Type="Int32" />
        </DeleteParameters>
        <UpdateParameters>
            <asp:Parameter Name="id" Type="Int32" />
            <asp:Parameter Name="parentId" Type="Int32" />
            <asp:Parameter Name="name" Type="String" />
            <asp:Parameter Name="publishTime" Type="DateTime" />
            <asp:Parameter Name="price" Type="Decimal" />
            <asp:Parameter Name="isGood" Type="Boolean" />
        </UpdateParameters>
    </asp:ObjectDataSource>
    <asp:ObjectDataSource ID="ObjectDataSource2" runat="server" OldValuesParameterFormatString="original_{0}"
        SelectMethod="GetTestById" TypeName="Test">
        <SelectParameters>
            <asp:ControlParameter ControlID="GridView1" Name="id" PropertyName="SelectedValue"
                Type="Int32" />
        </SelectParameters>
    </asp:ObjectDataSource>
</asp:Content>

DataSourceControl/Test.aspx.cs

Code
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class DataSourceControl_Test : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void ObjectDataSource1_Inserting(object sender, ObjectDataSourceMethodEventArgs e)
    {
        // 編程方式給參數賦值
        if (e.InputParameters["publishTime"] == null)
        {
            e.InputParameters["publishTime"] = DateTime.Now;
        }
    }

    protected void ObjectDataSource1_Inserted(object sender, ObjectDataSourceStatusEventArgs e)
    {
        // 錯誤處理
        if (e.Exception != null)
        {
            if (e.Exception.InnerException != null)
            {
                Exception inner = e.Exception.InnerException;

                if (inner is ArgumentException)
                {
                    string paramName = ((ArgumentException)inner).ParamName;
                    lblMsg.Text = string.Concat("參數 ", paramName, " 有問題");
                }
            }
        }
        else
        {
            int?[] ary = (int?[])e.ReturnValue;
            lblMsg.Text = "新插入信息的ID是：" + ary[0].ToString();
            lblMsg.Text += "<br />數據總數是：" + ary[1].ToString();

            lblMsg.Text += "<br />最小ID是：" + e.OutputParameters["minId"].ToString();
        }
    }

    protected void DetailsView1_ItemInserted(object sender, DetailsViewInsertedEventArgs e)
    {
        if (e.Exception != null)
        {
            // 錯誤已處理
            e.ExceptionHandled = true;
            // DetailsView保持插入狀態
            e.KeepInInsertMode = true;
        }
    }

    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        // 價格格式轉換為decimal格式
        if (e.NewValues["Price"] != null)
            e.NewValues["Price"] = decimal.Parse(e.NewValues["Price"].ToString(), System.Globalization.NumberStyles.Currency);
    }
}