Question

我遇到了这个名为Object必须实现IConvertible的错误。请帮我！我认为这是因为用户类型的下拉列表。即使我删除/注释掉下拉列表，我仍然会遇到此错误。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Data;
using System.Data.SqlClient;

public partial class Admin_Register : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(Helper.GetCon());

    protected void Page_Load(object sender, EventArgs e)
    {
            GetUserTypes();

    }

    void GetUserTypes()
    {
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "SELECT TypeID, TypeName FROM UserTypes";
        SqlDataReader data = cmd.ExecuteReader();
        ddlUserTypes.DataSource = data;
        ddlUserTypes.DataTextField = "TypeName";
        ddlUserTypes.DataValueField = "TypeID";
        ddlUserTypes.DataBind();
        con.Close();
    }

    bool IsRecordExisting(string email)
    {
        bool existing = true;
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "SELECT EmailAddress FROM Users WHERE EmailAddress=@EmailAddress";
        cmd.Parameters.Add("@EmailAddress", SqlDbType.VarChar).Value = email;
        SqlDataReader data = cmd.ExecuteReader();
        if (data.HasRows)
            existing = true;
        else
            existing = false;
        con.Close();
        return existing;
    }


    protected void btnRegister_Click(object sender, EventArgs e)
    {
        if (!IsRecordExisting(txtEmail.Text))
        {
            con.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = con;
            cmd.CommandText = "INSERT INTO Users VALUES (@EmailAddress, @Password, @TypeID, @FirstName, @LastName, @MiddleInitial, @Address, @TelNo, @CelNo, @Status";
            cmd.Parameters.Add("@EmailAddress", SqlDbType.VarChar).Value = txtEmail.Text;
            cmd.Parameters.Add("@Password", SqlDbType.VarChar).Value = Helper.CreateSHAHash(txtPassword.Text);

            cmd.Parameters.Add("@TypeID", SqlDbType.Int).Value = ddlUserTypes.SelectedValue;
            cmd.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = txtFN;
            cmd.Parameters.Add("@LastName", SqlDbType.VarChar).Value = txtLN;
            cmd.Parameters.Add("@MiddleInitial", SqlDbType.VarChar).Value = "";
            cmd.Parameters.Add("@Address", SqlDbType.VarChar).Value = "";
            cmd.Parameters.Add("@TelNo", SqlDbType.VarChar).Value = "";
            cmd.Parameters.Add("@CelNo", SqlDbType.VarChar).Value = "";
            cmd.Parameters.Add("@Status", SqlDbType.VarChar).Value = "Active";
            cmd.ExecuteNonQuery();
            con.Close();
            Helper.Log("0", "Register", "User Registration");
            Helper.ClearTextboxes(this.Controls);
            register.Visible = true;
        }
        else
        {
            register.Visible = false;
            error.Visible = true;
        }
    }
}

Answer 1

我在您的代码中发现了两个问题

<强>第一

请检查这些行

cmd.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = txtFN;
cmd.Parameters.Add("@LastName", SqlDbType.VarChar).Value = txtLN;

您将参数值设置为Texbox。您需要将文本框的文本设置为参数值。

cmd.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = txtFN.Text;
cmd.Parameters.Add("@LastName", SqlDbType.VarChar).Value = txtLN.Text;

<强>第二

下拉列表 SelectedValue 属性返回字符串值。你需要在分配时将字符串值转换为int类型。

请更改此行

 cmd.Parameters.Add("@TypeID", SqlDbType.Int).Value = ddlUserTypes.SelectedValue;

到

 cmd.Parameters.Add("@TypeID", SqlDbType.Int).Value = Convert.ToInt32(ddlUserTypes.SelectedValue);

对象必须使用ASP.NET实现IConvertible

1 个答案: