ASP.Net C＃无法更新图片，但是在将新图片插入数据库时​​成功

Question

我正在为ImageHandler使用.ashx文件。

这是我收到的错误消息，System.Data.dll中发生类型为'System.InvalidOperationException'的异常，但未在用户代码中处理

附加信息：当没有数据时，读取尝试无效。

This part showing the error
     SqlDataReader dr = cmd.ExecuteReader(); 
      dr.Read(); 
      context.Response.ContentType = dr["Image_Type"].ToString(); 
      context.Response.BinaryWrite((byte[])dr["Profile_Picture"]); 
      dr.Close();

这是我的ImageHandler.ashx：

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.Data;
using System.Configuration;
using System.IO;

public class ImageHandler : IHttpHandler {

  public void ProcessRequest (HttpContext context) {
  SqlConnection myConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["Register"].ConnectionString);
  myConnection.Open(); 
  string sql = "Select Profile_Picture, Image_Type from Member where Login_Id=@Name"; 
  SqlCommand cmd = new SqlCommand(sql, myConnection);
  cmd.Parameters.Add("@Name", SqlDbType.NVarChar).Value = context.Request.QueryString["Login_Id"]; 

  SqlDataReader dr = cmd.ExecuteReader(); 
  dr.Read(); 
  context.Response.ContentType = dr["Image_Type"].ToString(); 
  context.Response.BinaryWrite((byte[])dr["Profile_Picture"]); 
  dr.Close();
  myConnection.Close(); 
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}

这是我的UpdateProfile.aspx.cs：

    protected void btnSave_Click(object sender, EventArgs e)
    {
string constr = ConfigurationManager.ConnectionStrings["Register"].ConnectionString;
        string filename = Path.GetFileName(fuProfilePicture.PostedFile.FileName);
        string contentType = fuProfilePicture.PostedFile.ContentType;

        using (Stream fs = fuProfilePicture.PostedFile.InputStream)
        {
            using (BinaryReader br = new BinaryReader(fs))
            {
                byte[] bytes = br.ReadBytes((Int32)fs.Length);

                using (SqlConnection con1 = new SqlConnection(constr))
                {
                    string query1 = "Update Member Set Name = @name, 
                         Email = @email, Phone_Number = @phonenumber, 
                         Gender = gender, Date_Of_Birth = @dob, 
                         Password = @password, Login_Id = @loginid,
                         Student_ID = @studentid, 
                         Profile_Picture = @profilepicture 
                         WHERE Login_Id = '" + Request.QueryString["Login_Id"] + "'";
                    using (SqlCommand cmd1 = new SqlCommand(query1))
                    {

                        cmd1.Connection = con1;
                        cmd1.Parameters.AddWithValue("@imagename", filename);
                        cmd1.Parameters.AddWithValue("@imagetype", contentType);
                        cmd1.Parameters.AddWithValue("@profilepicture", bytes);
                        cmd1.Parameters.AddWithValue("@name", txtName.Text);
                        cmd1.Parameters.AddWithValue("@email", txtEmail.Text);
                        cmd1.Parameters.AddWithValue("@phonenumber", txtContactNumber.Text);
                        cmd1.Parameters.AddWithValue("@gender", ddlGender.SelectedItem.ToString());
                        cmd1.Parameters.AddWithValue("@dob", ddlDay.SelectedItem.ToString() + "/" + ddlMonth.SelectedItem.ToString() + "/" + txtYear.Text);
                        cmd1.Parameters.AddWithValue("@password", txtPassword.Text);
                        cmd1.Parameters.AddWithValue("@loginid", txtUsername.Text);
                        cmd1.Parameters.AddWithValue("@studentid", txtStudentID.Text);
                        con1.Open();
                        cmd1.ExecuteNonQuery();
                        con1.Close();
                    }
                }
            }
        }
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        sb.Append("<script type = 'text/javascript'>");
        sb.Append("window.onload=function(){");
        sb.Append("alert('");
        sb.Append("Update Successfuly!");
        sb.Append("')};");
        sb.Append("</script>");
        ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", sb.ToString());
    }


        }

Answer 1

也许是因为您忘记了性别上的@符号：

Phone_Number = @phonenumber, Gender = gender,