如何获取前一个页面的控件的值。

[zhoulier]

母版页：控件（textbox1,dropdownlist1,button1)C#代码如下

内容页:default.aspx(无内容);
内容页:default2.aspx(控件Gridview1)C#代码如下

调试正常无语法错误
问题点：在default.aspx页面，dropdownlist1选择第二个item，点击button1，转入default2.aspx页面,内容页显示的是默认值第一个item的结果。实际上没有将需要的值传递过来。请教如何解决？

[zhoulier]

问题已解决：主要修改代码如下

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string searchtype, searchwhat;
        //判断是否是跨页面传送,跨页传送就用PreviousPage传值。
        if (PreviousPage != null)
        {
            TextBox mptextbox = (TextBox)PreviousPage.Master.FindControl("TextBox1");
            DropDownList mpdropdownlist = (DropDownList)PreviousPage.Master.FindControl("DropDownList1");
            searchtype = mpdropdownlist.SelectedItem.Value.ToString();
            searchwhat = mptextbox.Text;
        }
        else
        {
            searchtype = Master.mpsearchtype;
            searchwhat = Master .mpsearchwhat;
        }
         

谢谢各位。

[zhoulier]

母版页：控件（textbox1,dropdownlist1,button1)C#代码如下

public partial class MasterPage : System.Web.UI.MasterPage
{
    public string mpsearchtype
    {
        get { return DropDownList1.SelectedItem.Value.ToString(); }
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        Server.Transfer("default2.aspx");
    }
}

内容页:default2.aspx(控件Gridview1)C#代码如下

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string searchtype = Master.mpsearchtype;
        TextBox mptextbox = (TextBox)Master.FindControl("TextBox1");
        DropDownList mpdropdownlist = (DropDownList)Master.FindControl("DropDownList1");
        //string searchtype=mpdropdownlist.SelectedItem.Value .ToString();
        string searchwhat = mptextbox.Text;
        // 1. Create the connection string and command string
        string connectionString =
             "Data Source=kingdee;Initial Catalog=aspnet;Persist Security Info=True;User ID=;Password=";
        string searchtable = "customer";
        if (searchtype == "fcustomerid" || searchtype =="fcustomername")
        {
            searchtable = "customer";
        }   
        string commandString =
            "Select * from " + searchtable + " where " + searchtype + " like '%" + searchwhat + "%'";
        
        // 2.   Pass the strings to the SqlDataAdapter constructor 
        SqlDataAdapter dataAdapter =
             new SqlDataAdapter(commandString, connectionString);

        // 3. Create a DataSet
        DataSet dataSet = new DataSet();

        // 4. fill the dataset object
        dataAdapter.Fill(dataSet, "customer");

        // 5. Get the table from the dataset
        DataTable dataTable = dataSet.Tables["customer"];

        // 6. Bind to the Gridview
        GridView1.DataSource = dataTable;
        GridView1.DataBind();

    }
}

[zhangyu_xl]

用previous属性的FindControl()方法。

[zhoulier]

[Quote=引用 2 楼 zhangyu_xl 的回复:]
用previous属性的FindControl()方法。
[/Quote]
能具体点吗？我是初学者

[zhoulier]

[Quote=引用 3 楼 zhoulier 的回复:]
引用 2 楼 zhangyu_xl 的回复:
用previous属性的FindControl()方法。

能具体点吗？我是初学者
[/Quote]
从default.aspx到default2.aspx正常了，但是default2.aspx本身出问题了，是不是应该在此之前先if一下呢？
错误如下
异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。
行 20: TextBox mptextbox=(TextBox )PreviousPage .Master .FindControl("TextBox1");

[LiloZhu]

TextBox mptextbox = (TextBox)PreviousPage.Master.FindControl("ContentPlaceHolder1").FindControl("TextBox1");

[xlong224]

TextBox mptextbox=(TextBox )PreviousPage .Master .FindControl("TextBox1");