级联下拉列表和重复项目的问题 [英] Problems with cascading dropdown and duplicate items
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问题描述
我有一个问题，我的动态下拉列表会产生重复的项目。
我选择了更改事件，我根据下拉数字1中选择的内容填写下拉数字2。但是每一个我填写它的时间，它是双重内容。我想我已经尝试了一切。
C＃代码
Hi, I have a problem that my dynamic dropdowns make duplicate items.
I selected change event, where I fill in the dropdown number 2 based on what is selected in dropdown number 1. But every time I fill it, it makes double content. And I think I've tried everything.
C# code
SelectedIndexChanged
protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
{
//PlaceHolder1.Controls.Clear();
XmlDocument doc = new XmlDocument();
doc.Load(Server.MapPath("./xmlReBikeInfo/InfoBikeResponse.xml"));
Table table = (Table)PlaceHolder1.FindControl("Table1");
if (table != null)
{
for (int i = 0; i < Rows; i++)
{
DropDownList ddl = (DropDownList)PlaceHolder1.FindControl("ddlBike_" + i + "");
//Use Request objects for getting the previous data of the dynamic textbox
string biketype = ddl.SelectedValue;
HiddenField hdnSize = (HiddenField)PlaceHolder1.FindControl("hdnSize_" + i + "");
DropDownList ddlSize = (DropDownList)PlaceHolder1.FindControl("ddlSize_" + i + "");
ddlSize.CssClass = "dropdown";
//ddlSize.SelectedValue = "";
ddlSize.Visible = true;
TextBox txt = (TextBox)PlaceHolder1.FindControl("txtPrice_" + i + "");
HiddenField hdnCykelPris = (HiddenField)PlaceHolder1.FindControl("txtHdnCykelPris_" + i);
HiddenField hdnAccPris = (HiddenField)PlaceHolder1.FindControl("txtHdnAccPris_" + i);
string number1;
string number2;
XDocument xdoc = XDocument.Load(Server.MapPath("./xmlReBikeInfo/InfoBikeResponse.xml"));
var bikeSizes = xdoc.Descendants("BikeType")
.Where(x => x.Element("TypeName").Value == biketype)
.SelectMany(x => x.Descendants("SizeName").Select(y => y.Value))
.ToList();
var bikePrice = xdoc.Descendants("BikeType")
.Where(x => x.Element("TypeName").Value == biketype)
.SelectMany(x => x.Descendants("TypePriceVat").Select(y => y.Value))
.ToList();
var bikeAcc = xdoc.Descendants("Accessorie")
.Where(x => x.Element("AccessorieName").Value == biketype)
.SelectMany(x => x.Descendants("AccessoriePriceVat").Select(y => y.Value))
.ToList();
decimal result = 0;
if (biketype == "0")
{
txt.Text = "";
}
if (biketype == "Touring")
{
foreach (string s in bikeSizes)
{
ddlSize.Items.Add(new ListItem(s + ""));
}
foreach (string p in bikePrice)
{
hdnCykelPris.Value = p.ToString();
string accPrice = "";
if (hdnAccPris.Value == "")
{
accPrice = "0";
}
else
{
accPrice = hdnAccPris.Value;
}
number1 = hdnCykelPris.Value;
number2 = accPrice.ToString();
result = decimal.Parse(number1) + decimal.Parse(number2);
txt.Text = result.ToString();
//txt.Text = hdnCykelPris.Value;
//litSum.Text = txt.Text;
}
ddlSize.Visible = true;
}
if (biketype == "Junior Bike")
{
foreach (string s in bikeSizes)
{
ddlSize.Items.Add(new ListItem(s + ""));
}
foreach (string p in bikePrice)
{
hdnCykelPris.Value = p.ToString();
string accPrice = "";
if (hdnAccPris.Value == "")
{
accPrice = "0";
}
else
{
accPrice = hdnAccPris.Value;
}
number1 = hdnCykelPris.Value;
number2 = accPrice.ToString();
result = decimal.Parse(number1) + decimal.Parse(number2);
txt.Text = result.ToString();
//txt.Text = hdnCykelPris.Value;
}
}
if (biketype == "MTB")
{
foreach (string s in bikeSizes)
{
ddlSize.Items.Add(new ListItem(s + ""));
}
foreach (string p in bikePrice)
{
hdnCykelPris.Value = p.ToString();
string accPrice = "";
if (hdnAccPris.Value == "")
{
accPrice = "0";
}
else
{
accPrice = hdnAccPris.Value;
}
number1 = hdnCykelPris.Value;
number2 = accPrice.ToString();
result = decimal.Parse(number1) + decimal.Parse(number2);
txt.Text = result.ToString();
//txt.Text = hdnCykelPris.Value;
}
}
if (biketype == "Classic E")
{
foreach (string s in bikeSizes)
{
ddlSize.Items.Clear();
ddlSize.Items.Add(new ListItem(s + ""));
//ddlSize.ClearSelection();
}
ddlSize.Visible = true;
foreach (string p in bikePrice)
hdnCykelPris.Value = p.ToString();
string accPrice = "";
if (hdnAccPris.Value == "")
{
accPrice = "0";
}
else
{
accPrice = hdnAccPris.Value;
}
number1 = hdnCykelPris.Value;
number2 = accPrice.ToString();
result = decimal.Parse(number1) + decimal.Parse(number2);
txt.Text = result.ToString();
}
}
我尝试了什么：
Clearselection方法，填充前清除项目方法。
这个方法
What I have tried:
Clearselection method, clear items method before filling.
And this method
public static void RemoveDuplicateItems(DropDownList ddl)
{
for (int i = 0; i < ddl.Items.Count; i++)
{
ddl.SelectedIndex = i;
string str = ddl.SelectedItem.ToString();
for (int counter = i + 1; counter < ddl.Items.Count; counter++)
{
ddl.SelectedIndex = counter;
string compareStr = ddl.SelectedItem.ToString();
if (str == compareStr)
{
ddl.Items.RemoveAt(counter);
counter = counter - 1;
}
}
}
}
推荐答案
你应该删除之前的重复项将集合绑定到下拉列表。
老实说，如果你不想在你的集合中重复，也许你应该检查将它们添加到数据库的机制，并防止它们被复制（如果可能的话）。
You should remove the duplicates before binding the collection to the dropdownlist.
In all honestly if you don't want duplicates in your collection, maybe you should examine the mechanism that adds them to the database, and prevent them from being duplicated (if that's possible).
我不确定我是否理解你...但是，如果你想获得独特的数据，你可以使用< a href =https://msdn.microsoft.com/en-us/library/system.linq.enumerable.distinct(v=vs.110).aspx> Distinct（）方法 [ ^ ]：
I'm not sure i understand you well... But, if you would like to get unique data, you can use Distinct() method[^]:
var bikeSizes = xdoc.Descendants("BikeType")
.Where(x => x.Element("TypeName").Value == biketype)
.SelectMany(x => x.Descendants("SizeName").Select(y => y.Value))
.Distinct() //here!
.ToList();
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