c# - How to select data from a DataTable with condition

Get DataRows array from DataTable that match the filter criteria
DataRowArrayFromADataTableWithFilter.aspx

<%@ Page Language="C#" AutoEventWireup="true" %>
<%@ Import Namespace="System.Data" %>

<!DOCTYPE html>
<script runat="server">
    void Button1_Click(object sender, System.EventArgs e)
    {
        DataTable dt = new DataTable();
        dt.TableName = "Books";

        DataColumn dc1 = new DataColumn();
        dc1.ColumnName = "BookID";
        dc1.DataType = typeof(int);
        dc1.AllowDBNull = false;
        dc1.Unique = true;

        DataColumn dc2 = new DataColumn();
        dc2.ColumnName = "BookName";
        dc2.DataType = typeof(string);

        DataColumn dc3 = new DataColumn();
        dc3.ColumnName = "Author";
        dc3.DataType = typeof(string);
        
        dt.Columns.AddRange(new DataColumn[] { dc1,dc2,dc3 });

        dt.Rows.Add(new object[] { 1, "Oracle SQL Tuning Pocket Reference", "Mark Gurry" });
        dt.Rows.Add(new object[] { 2, "Java Programming with Oracle JDBC", "Donald Bales" });
        dt.Rows.Add(new object[] { 3, "Oracle DBA Checklists Pocket Reference", "Quest Software" });

        GridView1.DataSource = dt;
        GridView1.DataBind();

        //this line return a DataRow array from DataTable
        DataRow[] drows = dt.Select("BookID < 3");
        for (int i = 0; i < drows.Length;i++ )
        {
            dt.Rows[i]["BookName"] = dt.Rows[i]["BookName"].ToString().ToLower();
        }

        Label1.Text = "After updating filtered rows (make BookName lower case , BookID < 3)";
            
        GridView2.DataSource = dt;
        GridView2.DataBind();
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>How to get a DataRow objects array from DataTable that match the filter criteria in ado.net</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h2 style="color:DarkBlue; font-style:italic;">
            How to get a DataRow objects array from
            <br /> DataTable that match the filter criteria in ado.net
        </h2>
        <hr width="550" align="left" color="CornFlowerBlue" />
        <asp:GridView 
            ID="GridView1"
            runat="server"
            BorderColor="Snow"
            ForeColor="Snow"
            Width="550"
            >
            <HeaderStyle BackColor="Purple" Height="35" />
            <RowStyle BackColor="Magenta" />
            <AlternatingRowStyle BackColor="MediumPurple" />
        </asp:GridView>
        <br />
        <asp:Label
             ID="Label1"
             runat="server"
             Font-Size="Large"
             ForeColor="SkyBlue"
             Font-Italic="true"
             >
        </asp:Label>
        <br /><br />
        <asp:GridView 
            ID="GridView2"
            runat="server"
            BorderColor="Snow"
            ForeColor="Snow"
            Width="550"
            >
            <HeaderStyle BackColor="Purple" Height="35" />
            <RowStyle BackColor="Magenta" />
            <AlternatingRowStyle BackColor="MediumPurple" />
        </asp:GridView>
        <asp:Button 
            ID="Button1"
            runat="server"
            OnClick="Button1_Click"
            Text="Populate GridView"
            Height="45"
            Font-Bold="true"
            ForeColor="DarkBlue"
            />
    </div>
    </form>
</body>
</html>
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