在Asp.net中填充逗号分隔的字符串以多选ListBox-C＃

Question

I have a List Box which i want to get selected from a comma separated string but my code is not working.

ASPX:

<asp:ListBox ID="ListBox1" runat="server" SelectionMode="Multiple">
    <asp:ListItem Value="1">aaa</asp:ListItem>
    <asp:ListItem Value="2">bbb</asp:ListItem>
    <asp:ListItem Value="3">ccc</asp:ListItem>
    <asp:ListItem Value="4">ddd</asp:ListItem>
    <asp:ListItem Value="5">eee</asp:ListItem>
    <asp:ListItem Value="6">fff</asp:ListItem>
</asp:ListBox>

ASPX.CS: (Code)

string listboxvalues = "2,1,5";
for (int i = 0; i < ListBox1.Items.Count; i++)
{
    foreach (string category in listboxvalues.ToString().Split(','))
    {
        if (category != ListBox1.Items[i].Value) continue;
            ListBox1.Items[i].Selected = true;
            break;
    }
}

Expected Result: (The expected result is what i am expecting but the code is not selecting anything)

<asp:ListBox ID="ListBox1" runat="server" SelectionMode="Multiple">
    <asp:ListItem Value="1" Selected="True">aaa</asp:ListItem>
    <asp:ListItem Value="2" Selected="True">bbb</asp:ListItem>
    <asp:ListItem Value="3">ccc</asp:ListItem>
    <asp:ListItem Value="4">ddd</asp:ListItem>
    <asp:ListItem Value="5" Selected="True">eee</asp:ListItem>
    <asp:ListItem Value="6">fff</asp:ListItem>
</asp:ListBox>

Answer 1

ASPX.CS: (Code)

string listboxvalues = "2,1,5";

//declare a list

List<string> items = new List<string>()

for (int i = 0; i < ListBox1.Items.Count; i++)
{
    foreach (string category in listboxvalues.ToString().Split(','))
    {
        if (category != ListBox1.Items[i].Value) continue;
            items.Add(category);
            break;
    }
}

//then in your ListBox1

listBox1.DataSource = items;
        listBox1.DisplayMember = "Item";
        listBox1.ValueMember = "Value";