How can I get the CheckBoxList selected values, what I have doesn't seem to work C#.NET/VisualWebPart

问题

I am creating a CheckBoxList in a class file and am using an HTMLTextWriter to render the control.

I\'m using the following code to store the selected values in a string:

string YrStr = \"\";
for (int i = 0; i < YrChkBox.Items.Count; i++)
{
    if (YrChkBox.Items[i].Selected)
    {
        YrStr += YrChkBox.Items[i].Value + \";\"; 
    }
}

I stepped through the code and it doesn\'t seem to hit the inside of the if statement & the selected value attribute is false every time ... Anyone have an idea of how I can address this?

I populate it using the following:

 YrChkBox.Items.Add(new ListItem(\"Item 1\", \"Item1\"));

回答1:

In your ASPX page you've got the list like this:

    <asp:CheckBoxList ID="YrChkBox" runat="server" 
        onselectedindexchanged="YrChkBox_SelectedIndexChanged"></asp:CheckBoxList>
    <asp:Button ID="button" runat="server" Text="Submit" />

In your code behind aspx.cs page, you have this:

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            // Populate the CheckBoxList items only when it's not a postback.
            YrChkBox.Items.Add(new ListItem("Item 1", "Item1"));
            YrChkBox.Items.Add(new ListItem("Item 2", "Item2"));
        }
    }

    protected void YrChkBox_SelectedIndexChanged(object sender, EventArgs e)
    {
        // Create the list to store.
        List<String> YrStrList = new List<string>();
        // Loop through each item.
        foreach (ListItem item in YrChkBox.Items)
        {
            if (item.Selected)
            {
                // If the item is selected, add the value to the list.
                YrStrList.Add(item.Value);
            }
            else
            {
                // Item is not selected, do something else.
            }
        }
        // Join the string together using the ; delimiter.
        String YrStr = String.Join(";", YrStrList.ToArray());

        // Write to the page the value.
        Response.Write(String.Concat("Selected Items: ", YrStr));
    }

Ensure you use the if (!IsPostBack) { } condition because if you load it every page refresh, it's actually destroying the data.

回答2:

Try something like this:

foreach (ListItem listItem in YrChkBox.Items)
{
    if (listItem.Selected)
    { 
       //do some work 
    }
    else 
    { 
      //do something else 
    }
}

回答3:

check boxlist selected values with seperator

 string items = string.Empty;
        foreach (ListItem i in CheckBoxList1.Items)
        {
            if (i.Selected == true)
            {
                items += i.Text + ",";
            }
        }
        Response.Write("selected items"+ items);

回答4:

An elegant way to implement this would be to make an extension method, like this:

public static class Extensions
{
    public static List<string> GetSelectedItems(this CheckBoxList cbl)
    {
        var result = new List<string>();

        foreach (ListItem item in cbl.Items)
            if (item.Selected)
                result.Add(item.Value);

        return result;
    }
}

I can then use something like this to compose a string will all values separated by ';':

string.Join(";", cbl.GetSelectedItems());

回答5:

// Page.aspx //

// To count checklist item

  int a = ChkMonth.Items.Count;
        int count = 0;

        for (var i = 0; i < a; i++)
        {
            if (ChkMonth.Items[i].Selected == true)
            {
                count++;
            }
        }

// Page.aspx.cs //

  // To access checkbox list item's value //
   string YrStrList = "";
        foreach (ListItem listItem in ChkMonth.Items)
        {
            if (listItem.Selected)
            {
                YrStrList = YrStrList + "'" + listItem.Value + "'" + ",";
            }

        }

        sMonthStr = YrStrList.ToString();

回答6:

// aspx.cs

// Load CheckBoxList selected items into ListBox

    int status = 1;
    foreach (ListItem  s in chklstStates.Items  )
    {
        if (s.Selected == true)
        {
            if (ListBox1.Items.Count == 0)
            {
                ListBox1.Items.Add(s.Text);

            }
            else
            {
                foreach (ListItem list in ListBox1.Items)
                {
                    if (list.Text == s.Text)
                    {
                        status = status * 0;

                    }
                    else
                    {
                        status = status * 1;
                    }
                }
                if (status == 0)
                { }
               else
                {
                    ListBox1.Items.Add(s.Text);
                }
                status = 1;
            }
        }
    }
}

来源：https://stackoverflow.com/questions/9523263/how-can-i-get-the-checkboxlist-selected-values-what-i-have-doesnt-seem-to-work