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c# - How to copy items from list to list without foreach


Copy list items to another list without foreach loop



The List class represents a strongly typed list of objects. This class provides methods to search, sort, and manipulate lists. The List class is the generic equivalent of the ArrayList class. The list is not guaranteed to be sorted. Elements of a list can be accessed using an integer index and the indexes are zero-based. The list accepts null as a valid value for reference types and allows duplicate elements.




The following .net c# tutorial code demonstrates how we can copy list items to another list without the foreach loop. Here we will use the List class specified constructor to create a list instance by copying items from another list.




The List class List<T>(IEnumerable<T>) constructor initializes a new instance of the List class that contains elements copied from the specified collection and has sufficient capacity to accommodate the number of elements copied.




The List(System.Collections.Generic.IEnumerable<T> collection) constructor has a parameter named collection. The collection parameter is the collection whose elements are copied to the new list.




This list constructor throws ArgumentNullException if the collection is null. The elements are copied onto the list in the same order they are read by the enumerator of the collection.





copy-items-from-list-to-list.aspx



<%@ Page Language="C#" AutoEventWireup="true"%>

<!DOCTYPE html>
<script runat="server">
    protected void Button1_Click(object sender, System.EventArgs e)
    {
        List<string> redcolors = new List<string> { "red", "indianred", "crimson", "pink" };

        Label1.Text = "Red Colors: ";
        foreach (string s in redcolors)
        {
            Label1.Text += s + " | ";
        }

        List<string> newredcolors = new List<string>(redcolors);

        Label1.Text += "<br />Copy Of Red Colors List: ";
        foreach (string s in newredcolors)
        {
            Label1.Text += s + " | ";
        }
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>c# example - copy items from list to list without foreach</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h2 style="color:DarkBlue; font-style:italic;">
            c# example - how to copy items from
            <br /> list to list without foreach
        </h2>
        <hr width="550" align="left" color="LightBlue" />  

        <asp:Label 
            ID="Label1" 
            runat="server"
            Font-Size="X-Large"
            >
        </asp:Label>
        <br /><br />
        <asp:Button 
            ID="Button1" 
            runat="server" 
            Text="copy items from list to list"
            OnClick="Button1_Click"
            Height="40"
            Font-Bold="true"
            />
    </div>
    </form>
</body>
</html>





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