c# - How to count rows in a DataTable

Count DataRows from a DataTable
CountDataRowObjectsFromDataTable.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 DBA Pocket Guide", "David C. Kreines" });
        dt.Rows.Add(new object[] { 2, "Oracle SQL*Plus: The Definitive Guide, Second Edition", "Jonathan Gennick" });
        dt.Rows.Add(new object[] { 3, "Oracle Utilities Pocket Reference", "Sanjay Mishra" });

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

        //this line count all DataRow from DataTable
        int totalRows = dt.Rows.Count;

        Label1.Text = "DataTable contains total DataRow objects: " + totalRows;
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>How to count total DataRow objects from a DataTable in ado.net</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h2 style="color:DarkBlue; font-style:italic;">
            How to count total DataRow
            <br /> objects from a DataTable in ado.net
        </h2>
        <hr width="350" align="left" color="CornFlowerBlue" />
        <asp:GridView 
            ID="GridView1"
            runat="server"
            BorderColor="Snow"
            ForeColor="Snow"
            Width="550"
            >
            <HeaderStyle BackColor="SaddleBrown" Height="35" />
            <RowStyle BackColor="Purple" />
            <AlternatingRowStyle BackColor="PaleVioletRed" />
        </asp:GridView>
        <br />
        <asp:Label
             ID="Label1"
             runat="server"
             Font-Size="X-Large"
             ForeColor="OrangeRed"
             Font-Italic="true"
             >
        </asp:Label>
        <br /><br />
        <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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