.ExecuteNonQuery() sql asp.net error

Question

This is my first time working with sql and asp.net. I am working on a few examples to ensure I have all the basics I need. I was walking though a tutorial and where everything should be working just fine, I am getting an .ExecuteNonQuery() Error. SqlException was unhandled by user code // Incorrect syntax near the keyword 'Table'.

If you have any pointers, let me know. I worked the tutorial twice, I'm sure I'm doing something wrong here. -Thanks

.CS Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Configuration;

namespace WebSite
{
public partial class _default : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);

    protected void Page_Load(object sender, EventArgs e)
    {
        con.Open();
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        SqlCommand cmd = new SqlCommand("insert into Table values('" + txtfName.Text + "','" + txtlName.Text + "','" + txtpNumber.Text + "')", con);
        cmd.ExecuteNonQuery();
        con.Close();
        Label1.Visible = true;
        Label1.Text = "Your DATA has been submitted";
        txtpNumber.Text = "";
        txtlName.Text = "";
        txtfName.Text = "";
    }
  }
}

.aspx File:

<form id="form1" runat="server">
<div class="auto-style1">

    <strong>Insert data into Database<br />
    <br />
    </strong>

</div>
    <table align="center" class="auto-style2">
        <tr>
            <td class="auto-style3">First Name:</td>
            <td class="auto-style4">
                <asp:TextBox ID="txtfName" runat="server" Width="250px"></asp:TextBox>
            </td>
        </tr>
        <tr>
            <td class="auto-style3">Last Name:</td>
            <td class="auto-style4">
                <asp:TextBox ID="txtlName" runat="server" Width="250px"></asp:TextBox>
            </td>
        </tr>
        <tr>
            <td class="auto-style3">Phone Number:</td>
            <td class="auto-style4">
                <asp:TextBox ID="txtpNumber" runat="server" Width="250px"></asp:TextBox>
            </td>
        </tr>
        <tr>
            <td class="auto-style3">&nbsp;</td>
            <td class="auto-style4">
                <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Submit" Width="150px" />
            </td>
        </tr>
    </table>
    <br />
    <br />
    <asp:Label ID="Label1" runat="server" ForeColor="#663300" style="text-align: center" Visible="False"></asp:Label>
    <br />
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT * FROM [Table]"></asp:SqlDataSource>
</form>

SQL Database:

CREATE TABLE [dbo].[Table] (
[Id]      INT          IDENTITY (1, 1) NOT NULL,
[fName]   VARCHAR (50) NOT NULL,
[lName]   VARCHAR (50) NOT NULL,
[pNumber] VARCHAR (50) NOT NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);

Answer 1

Usually this error message is caused by a single quote present in your input textboxes or by the use of a reserved keyword. Both problems are present in your query. The TABLE word is a reserved keyword for SQL Server and thus you should encapsulate it with square brackets, while for the possible presence of a single quote in the input text the correct approach is to use Parameterized Query like this

SqlCommand cmd = new SqlCommand("insert into [Table] values(@fnam, @lnam, @pNum)", con);
cmd.Parameters.AddWithValue("@fnam", txtfName.Text );
cmd.Parameters.AddWithValue("@lnam", txtlName.Text );
cmd.Parameters.AddWithValue("@pNum", txtpNumber.Text);
cmd.ExecuteNonQuery();

With this approach you shift the work to parse your input text to the framework code and you avoid problems with parsing text and Sql Injection

Also, I suggest to NOT USE a global variable to keep the SqlConnection reference. It is an expensive resource and, if you forget to close and dispose it, you could have a significant impact on the performance and the stability of your application.
For this kind of situations the using statement is all you really need

using(SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings
                             ["ConnectionString"].ConnectionString));
{
    con.Open();
    SqlCommand cmd = new SqlCommand("insert into [Table] values(@fnam, @lnam, @pNum)", con);
    cmd.Parameters.AddWithValue("@fnam", txtfName.Text );
    cmd.Parameters.AddWithValue("@lnam", txtlName.Text );
    cmd.Parameters.AddWithValue("@pNum", txtpNumber.Text);
    cmd.ExecuteNonQuery();
}

Of course remove the global variable and the open in the Page_Load