ASP.net - ＆＃34;没有给出一个或多个必需参数的值＆＃34;

Question

我想知道我是否可以获得一些帮助，因为我正在处理的某些代码出错！

点击我的登录按钮时，我在第37行得到以下信息： ＆＃34;没有给出一个或多个必需参数的值。

描述：执行当前Web请求期间发生了未处理的异常。请查看堆栈跟踪以获取有关错误及其源自代码的位置的更多信息。

异常详细信息：System.Data.OleDb.OleDbException：没有为一个或多个必需参数指定值。＆＃34;

有什么想法吗？

非常感谢

由于

杰克！ ：）

protected void btnLogin_Click（object sender，EventArgs e）     {

        OleDbConnection conn = new OleDbConnection(ConfigurationManager.ConnectionStrings["CameraWarehouseDB"].ConnectionString);
        //Opens connection with database
        conn.Open();

        //Declared a string - checks to see if username already exisits in the database.
        string checkusername = "SELECT COUNT (*) FROM [Customer] WHERE CustomerUserName= '" + txtUserName.Text + "'";

        //If count is 1, it means its already exisits, so cannot be used again and triggers alert
        OleDbCommand com = new OleDbCommand(checkusername, conn);
        //Replace removes any spaces the user make have accidentally inputed in the text box
        int temp = Convert.ToInt32(com.ExecuteScalar().ToString());
        conn.Close();
        if (temp == 1)
        {
            //Verying username and password - Checks for password in database based on entered username
            conn.Open();
            string checkpassword = "SELECT Password FROM [Customer] WHERE CustomerUserName= '" + txtUserName.Text + "'";
            OleDbCommand passwordcom = new OleDbCommand(checkpassword, conn);
            string password = passwordcom.ExecuteScalar().ToString();

            //Verify password based on entered password in password text box
            if (password == txtPassword.Text)
            {
                Session["New"]=txtUserName.Text;
                Response.Write("Password is correct");
            }
            else
            {
                Response.Write("Incorrect password entered, please try again");
            }
        }
            else
            {
                Response.Write("Incorrect user name entered, please try again");
            }
        conn.Close();
        }    
}