如何使用变量给数据源控件参数赋值、如何动态增减数据源控件参数并支持分页

一、如何使用变量给数据源控件参数赋值
      在VS2005中数据源控件的参数类型有六种：ControlParameter 、CookieParameter 、FormParameter 、ProfileParameter 、QueryStringParameter 、SessionParameter。利用这些参数类型可以很方便的给数据源控件的参数赋值。但 在实际编程中我们经常要使用变量给数据源控件的参数赋值，那么如何使用变量来赋值呢？
方法如下：
1、在前台代码中写好带参数的查询语句：
<asp:SqlDataSource ID="SqlDataSourcedown" runat="server" ConnectionString="<%$ ConnectionStrings:articleConnectionString %>"
                                            SelectCommand="SELECT TOP (15) id, name, type FROM kejian WHERE (isfabu = 1) AND (kemuid = @kemuid) AND (lianjiid=@lianjiid) ORDER BY downn DESC">
                                            <SelectParameters>
                                                <asp:Parameter Name="kemuid" />
                                                <asp:Parameter Name="lianjiid" />
                                            </SelectParameters>
                                        </asp:SqlDataSource>
2、在后台代码中加入如下语句：
     int kemuid = 0;
    int lianjiid = 0;
    protected void Page_Load(object sender, EventArgs e)
    {
        int id = Convert.ToInt32(Request.QueryString["id"]);
        string sql = "select kemuid,lianjiid from kejian where id=" + id;
        using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["articleConnectionString"].ConnectionString))
        {
            using (SqlCommand command = new SqlCommand(sql, connection))
            {
                connection.Open();
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    if (reader.Read())
                    {
                        kemuid = (int)reader["kemuid"];
                        lianjiid = (int)reader["lianjiid"];
                    }
                }
            }
        }
            this.SqlDataSourcedown.SelectParameters.Clear();
            this.SqlDataSourcedown.SelectParameters.Add("kemuid", System.TypeCode.Int32, kemuid.ToString());
            this.SqlDataSourcedown.SelectParameters.Add("lianjiid", System.TypeCode.Int32, lianjiid.ToString());   
    }
请注意前后台代码中的红色部分，前后台代码中参数名一定要一致。就能实现使用变量来给参数赋值了。
是不是很简单很方便呢？
二、如何动态增减数据源控件参数并支持分页
适于环境：
页面search.aspx接受两个查询变量kemu及name，当kemu=0时进行全部科目的查询，当kemu！=0时进行当前科目的查询，并且要求对查询的结果进行分页。
实现方法：
在前台代码中加入：
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:articleConnectionString %>"
        SelectCommand="SELECT kejian.id, kejian.name, kejian.huanjing, kejian.type, kejian.downn, kejian.isfabu, kejian.stars, kejian.size, kejian.kemuid, kejian.updowntime, kemu.name AS kemu, lianji.name AS lianji FROM kejian INNER JOIN kemu ON kejian.kemuid = kemu.id INNER JOIN lianji ON kejian.lianjiid = lianji.id WHERE (kejian.name LIKE N'%' + @name + N'%') AND (kejian.kemuid = @kemu) AND (kejian.isfabu = 1) ORDER BY kejian.updowntime DESC">
        <SelectParameters>
            <asp:Parameter Name="name" />
            <asp:Parameter Name="kemu" />
        </SelectParameters>
    </asp:SqlDataSource>
在后台代码中加入：
 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
                   GridViewDataBind(Convert.ToInt32(Request.QueryString["kemu"]), Request.QueryString["name"]);
         }    
    }

    private void GridViewDataBind(int kemu, string  name)
    {
        string sql = "SELECT kejian.id, kejian.name, kemu.name AS kemu, lianji.name AS lianji, kejian.huanjing, kejian.type, kejian.downn, kejian.stars, kejian.size, kejian.kemuid ";
        sql += " FROM kejian INNER JOIN  kemu ON kejian.kemuid = kemu.id INNER JOIN lianji ON kejian.lianjiid = lianji.id ";
        sql += " WHERE (kejian.isfabu = 1) ";

        if (kemu == 0)
        {
            sql += " AND (kejian.name LIKE N'%' + @name + N'%') ORDER BY kejian.updownuserid DESC";
            this.SqlDataSource1.SelectParameters.Clear();
            this.SqlDataSource1.SelectParameters.Add("name", System.TypeCode.String, name);
        }
        else
        {
            sql += " AND (kejian.kemuid = @kemu) AND (kejian.name LIKE N'%' + @name + N'%') ORDER BY kejian.updownuserid DESC";
            this.SqlDataSource1.SelectParameters.Clear();
            this.SqlDataSource1.SelectParameters.Add("kemu", System.TypeCode.String, kemu.ToString());
            this.SqlDataSource1.SelectParameters.Add("name", System.TypeCode.String, name);
        }

        SqlDataSource1.SelectCommand = sql;
    }

    protected void GridView1_PageIndexChanged(object sender, EventArgs e)
    {
        GridViewDataBind(Convert.ToInt32(Request.QueryString["kemu"]), Request.QueryString["name"]);
    }