如何在 ASP.NET C# 中使用 foreach 获取 CheckBoxList 中所选项目的值？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/18924147/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to get values of selected items in CheckBoxList with foreach in ASP.NET C#?
提问by Amin AmiriDarban
I have a CheckBoxList like this:
我有一个这样的 CheckBoxList：
<asp:CheckBoxList ID="CBLGold" runat="server" CssClass="cbl">
<asp:ListItem Value="TGJU"> TG </asp:ListItem>
<asp:ListItem Value="GOLDOZ"> Gold </asp:ListItem>
<asp:ListItem Value="SILVEROZ"> Silver </asp:ListItem>
<asp:ListItem Value="NERKH"> NE </asp:ListItem>
<asp:ListItem Value="TALA"> Tala </asp:ListItem>
<asp:ListItem Value="YARAN"> Sekeh </asp:ListItem>
</asp:CheckBoxList>
Now I want to get the value of the selected items from this CheckBoxList using foreach, and put the values into a list.
现在我想使用 foreach 从这个 CheckBoxList 中获取所选项目的值，并将这些值放入一个列表中。
采纳答案by Tim Schmelter
Note that I prefer the code to be short.
请注意，我更喜欢简短的代码。
List<ListItem> selected = CBLGold.Items.Cast<ListItem>()
.Where(li => li.Selected)
.ToList();
or with a simple foreach:
或者用一个简单的foreach：
List<ListItem> selected = new List<ListItem>();
foreach (ListItem item in CBLGold.Items)
if (item.Selected) selected.Add(item);
If you just want the ListItem.Value:
如果您只想要ListItem.Value：
List<string> selectedValues = CBLGold.Items.Cast<ListItem>()
.Where(li => li.Selected)
.Select(li => li.Value)
.ToList();
回答by mreyeros
Good afternoon, you could always use a little LINQ to get the selected list items and then do what you want with the results:
下午好，您总是可以使用一点 LINQ 来获取选定的列表项，然后对结果执行您想要的操作：
var selected = CBLGold.Items.Cast<ListItem>().Where(x => x.Selected);
// work with selected...
回答by Arif Ansari
foreach (ListItem item in CBLGold.Items)
{
if (item.Selected)
{
string selectedValue = item.Value;
}
}
回答by KyleMit
Following suit from the suggestions here, I added an extension method to return a list of the selected items using LINQ for any type that Inherits from System.Web.UI.WebControls.ListControl.
遵循此处的建议，我添加了一个扩展方法，以使用 LINQ 为从.System.Web.UI.WebControls.ListControl
Every ListControlobject has an Itemsproperty of type ListItemCollection. ListItemCollectionexposes a collection of ListItems, each of which have a Selectedproperty.
每个ListControl对象都有一个Items类型的属性ListItemCollection。 ListItemCollection公开 的集合ListItems，每个集合都有一个Selected属性。
C Sharp:
C锐：
public static IEnumerable<ListItem> GetSelectedItems(this ListControl checkBoxList)
{
return from ListItem li in checkBoxList.Items where li.Selected select li;
}
Visual Basic:
视觉基础：
<Extension()> _
Public Function GetSelectedItems(ByVal checkBoxList As ListControl) As IEnumerable(Of ListItem)
Return From li As ListItem In checkBoxList.Items Where li.Selected
End Function
Then, just use like this in either language:
然后，在任何一种语言中都这样使用：
myCheckBoxList.GetSelectedItems()
回答by Gopal Reddy Vinnamala
string s= string.Empty
for (int i = 0; i < Chkboxlist.Items.Count; i++)
{
if (Chkboxlist.Items[i].Selected)
{
s+= Chkboxlist.Items[i].Value + ";";
}
}
回答by Rohini Yejju
List<string> values =new list<string>();
foreach(ListItem Item in ChkList.Item)
{
if(Item.Selected)
values.Add(item.Value);
}
回答by Slint
In my codebehind i created a checkboxlist from sql db in my Page_Load event and in my button_click event did all the get values from checkboxlist etc.
在我的代码隐藏中，我从 Page_Load 事件中的 sql db 创建了一个复选框列表，并在我的 button_click 事件中从复选框列表等中获取了所有值。
So when i checked some checkboxes and then clicked my button the first thing that happend was that my page_load event recreated the checkboxlist thus not having any boxes checked when it ran my get checkbox values... I've missed to add in the page_load event the if (!this.IsPostBack)
因此，当我检查一些复选框然后单击我的按钮时，发生的第一件事是我的 page_load 事件重新创建了复选框列表，因此在运行我的获取复选框值时没有选中任何框......我错过了添加 page_load 事件if (!this.IsPostBack)
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
// db query and create checkboxlist and other
SqlConnection dbConn = new SqlConnection(WebConfigurationManager.ConnectionStrings["ConnString"].ConnectionString);
string query;
try
{
query = "SELECT [name], [mail] FROM [users]";
dbConn.Open();
SqlDataAdapter da = new SqlDataAdapter(query, dbConn);
DataSet ds = new DataSet();
da.Fill(ds);
if (ds.Tables[0].Rows.Count != 0)
{
checkboxlist1.DataSource = ds;
checkboxlist1.DataTextField = "name";
checkboxlist1.DataValueField = "mail";
checkboxlist1.DataBind();
}
else
{
Response.Write("No Results found");
}
}
catch (Exception ex)
{
Response.Write("<br>" + ex);
}
finally
{
dbConn.Close();
}
}
}
protected void btnSend_Click(object sender, EventArgs e)
{
string strChkBox = string.Empty;
foreach (ListItem li in checkboxlist1.Value)
{
if (li.Selected == true)
{
strChkBox += li.Value + "; ";
// use only strChkBox += li + ", "; if you want the name of each checkbox checked rather then it's value.
}
}
Response.Write(strChkBox);
}
And the output was as expected, a semicolon separeted list for me to use in a mailsend function:
输出符合预期，分号分隔列表供我在 mailsend 函数中使用：
[email protected]; [email protected]; [email protected]
A long answer to a small problem. Please note that i'm far from an expert at this and know that there are better solutions then this but it might help out for some.
一个小问题的长答案。请注意，我远不是这方面的专家，并且知道有比这更好的解决方案，但它可能对某些人有所帮助。
回答by teapeng
To top up on @Tim Schmelter, in which to get back the List<int>instead,
为@Tim Schmelter 充值，在其中取回List<int>，
List<string> selectedValues = CBLGold.Items.Cast<ListItem>()
.Where(li => li.Selected)
.Select(li => li.Value)
.Select(int.Parse)
.ToList();
