dropdownlist确定传选中的值问题．在线等．急
我现在用dropdownlist做了一个三级联动,我想用三级联动选出来的ID用post的方法(就是as.asp?id=19的方法)传到另一个页面.(我的意思是:     品牌(下拉)   系列(下拉)   具体某一个产品(下拉)     确定按钮　当我按下确定时，就能把我选好的产品ＩＤ值传来我指定的页面．怎么实现)

cs源码
if(!IsPostBack)
{
ddlCategoryBind();

ddlCategory1Bind();
ddlCategory2Bind();
ddlCategory3Bind();



}


}


private   void   ddlCategoryBind()
{
Db.Category   myCategory   =   new   Db.Category();

DataSet   ds   =   myCategory.dsCategoryDeepID4( "4 ");
for(int   i=0;i <ds.Tables[0].Rows.Count;i++)
{
if(ds.Tables[0].Rows[i][2].ToString()== "001 ")
{
ds.Tables[0].Rows[i][3]   =   ds.Tables[0].Rows[i][3].ToString();
}
else
{
for(int   j=1;j <int.Parse(ds.Tables[0].Rows[i][2].ToString());j++)
{
ds.Tables[0].Rows[i][3]   =   "|__ "   +   ds.Tables[0].Rows[i][3].ToString();
}
}
}

ddlCategory.DataSource   =   ds.Tables[0].DefaultView;
ddlCategory.DataTextField   =   "Category ";
ddlCategory.DataValueField   =   "OrderID ";
ddlCategory.DataBind();
}

private   void   ddlCategory1Bind()
{
Db.Category   myCategory   =   new   Db.Category();

DataSet   ds   =   myCategory.dsCategoryFatherID4(ddlCategory.SelectedValue);

ddlCategory1.DataSource   =   ds.Tables[0].DefaultView;
ddlCategory1.DataTextField   =   "Category ";
ddlCategory1.DataValueField   =   "OrderID ";
ddlCategory1.DataBind();
Label4.Text=ddlCategory.SelectedValue;
}

private   void   ddlCategory2Bind()
{
Db.Category   myCategory   =   new   Db.Category();
Label1.Text   =   ddlCategory1.SelectedValue;
DataSet   ds   =   myCategory.dsCategoryFatherID41(ddlCategory1.SelectedValue);

ddlCategory2.DataSource   =   ds.Tables[0].DefaultView;
ddlCategory2.DataTextField   =   "proname ";
ddlCategory2.DataValueField   =   "id ";
ddlCategory2.DataBind();
Label2.Text   =   ddlCategory2.SelectedValue;
}
private   void   ddlCategory3Bind()
{
Db.Category   myCategory   =   new   Db.Category();
Label1.Text   =   ddlCategory2.SelectedValue;
DataSet   ds   =   myCategory.dsCategoryFatherID41(ddlCategory2.SelectedValue);

ddlCategory3.DataSource   =   ds.Tables[0].DefaultView;
ddlCategory3.DataTextField   =   "proname ";
ddlCategory3.DataValueField   =   "id ";
ddlCategory3.DataBind();
// Label2.Text   =   ddlCategory2.SelectedValue;
}

private   void   ddlCategory_SelectedIndexChanged(object   sender,   System.EventArgs   e)
{
ddlCategory1Bind();
}

private   void   ddlCategory1_SelectedIndexChanged(object   sender,   System.EventArgs   e)
{
ddlCategory2Bind();
}

private   void   ddlCategory2_SelectedIndexChanged(object   sender