Question

我创建了一个包含3个DropDownLists和一个搜索按钮的搜索功能。如何在同一页面上显示它？

这是我的代码：

public partial class Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            //read sql server connection string from web.config file
            string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
            SqlConnection conn = new SqlConnection(constring);
            DataTable dt = new DataTable("emed_province");

            using (conn)
            {
                conn.Open();
                SqlCommand comm = new SqlCommand("SELECT *  FROM emed_province ORDER BY PROVINCE_NAME ASC", conn);
                SqlDataAdapter adptr = new SqlDataAdapter(comm);
                adptr.Fill(dt);
            }

            ddlProvince.DataSource = dt;
            ddlProvince.DataTextField = "PROVINCE_NAME";
            ddlProvince.DataValueField = "PROVINCE_CODE";
            ddlProvince.DataBind();
        }
    }

    protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e)
    {
        string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
        SqlConnection conn = new SqlConnection(constring);
        DataTable dt = new DataTable("emed_province");

        using (conn)
        {
            conn.Open();
            PROVINCE_CODE = '" + ddlProvince.SelectedValue + "'", conn);
            SqlCommand comm = new SqlCommand("SELECT * FROM emed_city WHERE PROVINCE_CODE =@pcode", conn);
            comm.Parameters.AddWithValue("@pcode", ddlProvince.SelectedValue);
            SqlDataAdapter adptr = new SqlDataAdapter(comm);
            adptr.Fill(dt);

            SqlParameter param = new SqlParameter();
            param.ParameterName = "@pcode";
            param.Value = ddlProvince;

            comm.Parameters.Add(param);
        }
        ddlCity.DataSource = dt;
        ddlCity.DataTextField = "CITY_NAME";
        ddlCity.DataValueField = "CITY_CODE";
        ddlCity.DataBind();
    }

    protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)
    {
        string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
        SqlConnection conn = new SqlConnection(constring);
        DataTable dt = new DataTable("emed_city");

        using (conn)
        {
            conn.Open();
        PROVINCE_CODE = '" + ddlProvince.SelectedValue + "'", conn);
            SqlCommand comm = new SqlCommand("SELECT * FROM emed_doctors_hospitals     WHERE CITY_CODE =@ccode", conn);
            comm.Parameters.AddWithValue("@ccode", ddlCity.SelectedValue);
            SqlDataAdapter adptr = new SqlDataAdapter(comm);
            adptr.Fill(dt);

            SqlParameter param = new SqlParameter();
            param.ParameterName = "@ccode";
            param.Value = ddlCity;

            comm.Parameters.Add(param);
        }
        ddlSched.DataSource = dt;
        ddlSched.DataTextField = "SCHEDULE";
        ddlSched.DataValueField = "HOSPITAL_CODE";
        ddlSched.DataBind();
    }
    protected void Button1_Click(object sender, EventArgs e)
    {

    }
}

当有人在DropDownList中选择一个值并点击该按钮时，它将显示省，城市和特定时间表中可用的医生列表。

Answer 1

您基本上需要做的是以声明方式将控件放在ASPX页面中：

<asp:DropDownList id="ddlSche" runat="server" />

您可以使用ddlSched.SelectedValue和类似方法在Page_Load中计算结果。

基本上，你使用按钮的onclick处理程序来处理这类事情：但是，由于您已经有SelectedIndexChanged事件，因此您似乎正走在正确的轨道上。当用户回发页面并且索引被更改时（或者换句话说，用户选择DropDownList中当前选择之外的其他内容），它被触发。

Answer 2

检查此样本。我在这个例子中使用了SQLDatasource和SelectParameters（你可以用你自己的对象数据源，自定义绑定等替换它。）SQLDataSource Select Parameters
第二个下拉列表会在第一个下拉列表更改时自动填充
On Button即使我只是选择每个下拉列表中当前选择的值（您可以以相同的方式选择您的医生列表）

ASPX

    <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Cascading DropDown.aspx.cs"
    Inherits="Cascading_DropDown" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">
    <title></title> </head> <body>
    <form id="form1" runat="server">
    <div>
        <label>
            Category:</label>
        <asp:DropDownList ID="ddlCategories" runat="server" AppendDataBoundItems="True" AutoPostBack="True"
            DataSourceID="sdsCategory" DataTextField="CategoryName" DataValueField="CategoryID"
            OnSelectedIndexChanged="ddlCategories_SelectedIndexChanged">
            <asp:ListItem Text="-Select-" Value="" />
        </asp:DropDownList>
        <br />
        <label>
            Products:</label>
        <asp:DropDownList ID="ddlProducts" runat="server" DataSourceID="sdsProducts" DataTextField="ProductName"
            DataValueField="ProductID">
        </asp:DropDownList>
        <asp:Button ID="Button1" runat="server" Text="Search Prodcut" OnClick="Button1_Click" />
        &nbsp;<asp:Label ID="lblSelectedValues" runat="server"></asp:Label>
    </div>
    <asp:SqlDataSource ID="sdsCategory" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
        SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories] ORDER BY [CategoryName]">
    </asp:SqlDataSource>
    <asp:SqlDataSource ID="sdsProducts" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
        SelectCommand="SELECT [ProductID], [ProductName] FROM [Alphabetical list of products] WHERE ([CategoryID] = @CategoryID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="ddlCategories" Name="CategoryID" PropertyName="SelectedValue"
                Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>
    </form> </body> </html>

.CS

protected void Page_Load(object sender, EventArgs e)
{

}
protected void ddlCategories_SelectedIndexChanged(object sender, EventArgs e)
{
    if (ddlCategories.SelectedValue == "")
    {
        ddlProducts.Items.Clear();
        ddlProducts.SelectedIndex = -1;
    }

}
protected void Button1_Click(object sender, EventArgs e)
{
    lblSelectedValues.Text = "You selected Category:" + ddlCategories.SelectedItem.Text + " & prodcut:" + ddlProducts.SelectedItem.Text;
}

您可以在像Abel所说的那样的表格上删除网格视图。在您的按钮点击事件中，获取每个下拉列表选择的值＆amp;执行您的查询＆amp;像您正在使用下拉列表一样对数据视图进行数据处理。

使用搜索按钮搜索并显示三个下拉列表

2 个答案: