ASP.NET ListBox 互傳

ASP.NET ListBox 互傳


HTML:

<asp:ListBox ID="ListBox1" runat="server" SelectionMode="Multiple">
    <asp:ListItem>a</asp:ListItem>
    <asp:ListItem>b</asp:ListItem>
    <asp:ListItem>c</asp:ListItem>
</asp:ListBox>
<asp:Button ID="Button1" runat="server" Text="Add" onclick="Button1_Click" />
 
<asp:ListBox ID="ListBox2" runat="server" SelectionMode="Multiple">
</asp:ListBox>
<asp:Button ID="Button2" runat="server" Text="Del" onclick="Button2_Click" />

C#:

    protected void Button1_Click(object sender, EventArgs e)
    {
        //單選add時用下列這行
        //ListBox2.Items.Add(ListBox1.SelectedItem);
 
        //多選add用迴圈
        for (int i = 0; i < ListBox1.Items.Count; i++)
        {
            if (ListBox1.Items[i].Selected)
            {
                ListBox2.Items.Add(ListBox1.Items[i]);
            }
        }
    }
 
    protected void Button2_Click(object sender, EventArgs e)
    {
        //單選del
        //ListBox2.Items.RemoveAt(ListBox2.SelectedIndex);
 
        //多選del用迴圈
        for (int i = ListBox2.Items.Count - 1; i >= 0; i--)
        {
            if (ListBox2.Items[i].Selected)
            {
                ListBox2.Items.RemoveAt(i);
            }
        }
    }