How to set multiple selections in ASP.NET ListBox?

I can’t find a way to select multiple items in an ASP.NET ListBox in the code behind? Is this something needs to be done in Javascript?

Answers:

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Method 1

You will have to use FindByValue method of the ListBox

foreach (string selectedValue in SelectedValuesArray)
                    {
                        lstBranch.Items.FindByValue(selectedValue).Selected = true;
                    }

Method 2

Here’s a C# sample

(aspx)

<form id="form1" runat="server">
        <asp:ListBox ID="ListBox1" runat="server" >
            <asp:ListItem Value="Red" />
            <asp:ListItem Value="Blue" />
            <asp:ListItem Value="Green" />
        </asp:ListBox>
        <asp:Button ID="Button1" 
                    runat="server" 
                    onclick="Button1_Click" 
                    Text="Select Blue and Green" />
</form>

(Code Behind)

protected void Button1_Click(object sender, EventArgs e)
{
     ListBox1.SelectionMode = ListSelectionMode.Multiple;            
     foreach (ListItem item in ListBox1.Items)
     {
          if (item.Value == "Blue" || item.Value == "Green")
          {
               item.Selected = true;
          }
     }
}

Method 3

this is the VB code to do so…

myListBox.SelectionMode = Multiple
For each i as listBoxItem in myListBox.Items
  if i.Value = WantedValue Then
      i.Selected = true
  end if 
Next

Method 4

In C#:

foreach (ListItem item in ListBox1.Items)
{
    item.Attributes.Add("selected", "selected");
}

Method 5

I like where bill berlington is going with his solution. I don’t want to iterate through the ListBox.Items for each item in my array. Here is my solution:

foreach (int index in indicesIntArray)
{
    applicationListBox.Items[index].Selected = true;
}

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0