如何在Asp.Net C#中填充依赖下拉列表
本文关键字:填充 依赖 下拉列表 Net Asp | 更新日期: 2023-09-27 17:50:17
我想填充TWO下拉列表,根据第一个下拉列表的选择,第二个下拉列表将被填充。
示例:
就像我有两个下拉列表,即1.ddlCountry和2.ddlState
现在,当选择国家时,根据所选的国家,与该国家相关的States将填充在State下拉列表中。我想通过在Asp.Net中用C#编码语言重新加载整个页面来实现这一点。
我怎样才能达到同样的目的?
Dropdownlist
通过执行查询从数据库中获取数据。
- 您可以按照
Naresh
的指示使用AJAX toolkit CascadingDropDown
。或 - 使用ajax更新面板,并将所有的
Dropdowns
都保存在其中。这样整个页面就不会在更改下拉值时加载
您没有将代码提供给进一步的解决方案。
protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
{
FillStateByCountry();
}
protected void ddlState_SelectedIndexChanged(object sender, EventArgs e)
{
FillLocationByCountryandState();
}
private void FillStateByCountry()
{
DataSet dstFillState;
int CountryId = Convert.ToInt32(ddlCountry.SelectedValue.ToString());
dstFillState = Tbl_State.FillDDLState(CountryId);
ddlState.DataSource = dstFillState;
ddlState.DataTextField = "State";
ddlState.DataValueField = "Id";
ddlState.DataBind();
}
类似的FillLocationByCountryandState();
在表单中添加两个下拉列表,并将其命名为cmbStates
、cmbCities
当您从cmbStates(dropwdownlist)
中选择州名称时,cmbCities(dropdownlist)
会根据州名称(cmbStates(生成城市
通过从数据库提取数据
private void Form1_Load(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("server=pbs-server;database=p2p;user id=shekar;password=sekhar@1346");
SqlCommand cmd = new SqlCommand("select states from Country", con);
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(cmd);
con.Open();
da.Fill(ds, "Country");
cmbStates.DataSource = ds.Tables[0];
cmbStates.SelectedValue = 0;
con.Close();
}
private void cmbStates_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("server=xxxx;database=xxxx;user id=xxxxr;password=xxxxxx");
SqlCommand cmd = new SqlCommand("select cities from States where cityname = 'cmbStates.SelectedItem.ToString()'", con);
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(cmd);
con.Open();
da.Fill(ds, "States");
cmbCities.DataSource = ds.Tables[0];
cmbCities.SelectedValue = 0;
con.Close();
}
或
手动添加项目
namespace DropDownlist
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
cmbStates.Items.Add("Andhra Pradesh");
cmbStates.Items.Add("Tamilnadu");
cmbStates.Items.Add("Karnataka");
cmbStates.SelectedValue = 0;
}
private void cmbStates_SelectedIndexChanged(object sender, EventArgs e)
{
if (cmbStates.SelectedItem.ToString() == "Andhra Pradesh")
{
cmbCities.Items.Clear();
cmbCities.Items.Add("Hyderabad");
cmbCities.Items.Add("Guntur");
cmbCities.Items.Add("Vijayawada");
cmbCities.SelectedValue = 0;
}
else if (cmbStates.SelectedItem.ToString() == "Tamilnadu")
{
cmbCities.Items.Clear();
cmbCities.Items.Add("Chennai");
cmbCities.Items.Add("Coimbatore");
cmbCities.Items.Add("ooty");
cmbCities.SelectedValue = 0;
}
else if (cmbStates.SelectedItem.ToString() == "Karnataka")
{
cmbCities.Items.Clear();
cmbCities.Items.Add("Bangalore");
cmbCities.Items.Add("Mangalore");
cmbCities.SelectedValue = 0;
}
else
{
MessageBox.Show("Please Select any value");
}
}
}
}