Javascript 我试图在sql server中存储数据，但遇到了一个错误，我不知道如何修复

我正在尝试将用户名、电子邮件和他们的消息存储在我的联系人页面上。当我运行我的网站，进入联系人页面，在联系人表单中键入所有详细信息，然后单击发送按钮（发送按钮称为submitBtn）时，我得到了您可以在下图中看到的错误

错误消息：

c代码：此c代码用于发送按钮

protected void submitBtn_Click(object sender, EventArgs e)
    {
        try
        {
            //Create the conection string and open the conn
            SqlConnection conne = new SqlConnection(ConfigurationManager.ConnectionStrings["Fasthosts_MMConnectionString"].ConnectionString);
            //Open the connection string
            conne.Open();

            //Get all the values from the text boxes etc and pass them over to the DB
            string insertQuery = "insert into Contact(UserName, Email, Message) " +
                "values(@UserName, @Email, @Message)";
            SqlCommand com = new SqlCommand(insertQuery, conne);

            //Get values from the controls such as the text boxes and pass them over to the DB
            com.Parameters.AddWithValue("@UserName", tbUserName.Text);
            com.Parameters.AddWithValue("@Message", userMessage.Text);
            com.Parameters.AddWithValue("@Email", userEmail.Text);

            //This actually executes the query with the given values above.
            com.ExecuteNonQuery();

            //Dispose the connection string once the data has been passed over the DB
            conne.Close();

        }
        catch (Exception problem)
        {
            //throw Exception ;
            Response.Write("Error Message: " + problem.ToString());
            throw;

        }
    }

html代码：

 <div id="contactForm" class="contactForm">
    <div id="formHeader" class="formHeader">
        <h1 id="message">Contact Us :)</h1>
    </div>
    <div id="formBody" class="formBody">
        <form action="homepage.aspx" method="POST" name="contactForm">
            <div class="inputContainer">
                <label for="userName">
                    <i class="fa fa-lg fa-fw fa-user"></i>
                </label>
                <asp:TextBox ID="tbUserName" placeholder="John Smith" runat="server"></asp:TextBox>
                <!--<input name="name" id="userName" type="text" placeholder="John Smith">-->
            </div>
            <div class="inputContainer">
                <label for="userEmail">
                    <i class="fa fa-lg fa-fw fa-envelope"></i>
                </label>                
                <asp:TextBox ID="userEmail" placeholder="jsmith@domain.com" runat="server"></asp:TextBox>
            </div>
            <div class="inputContainer">                
                <asp:TextBox ID="userMessage" rows="10" placeholder="Enter your message" runat="server" Height="100px"></asp:TextBox>
            </div>
            <!--<input id="submitBtn1" class="submitBtn" type="submit" value="Send">-->
            <asp:Button ID="submitBtn" Class="submitBtn" runat="server" Text="Send" OnClick="submitBtn_Click" />
        </form>
    </div>

---

在源代码中page指令的第一行中编写此代码

<%@ Page EnableEventValidation="false" %>

为什么将其标记为SQL Server？mybe，因为它与在SQL Server中存储数据有关。

<%@ Page EnableEventValidation="false" %>