如何上传图片答案

【问题标题】：How To Upload Image如何上传图片
【发布时间】：2014-03-11 16:56:50
【问题描述】：

上传文件时出现以下错误。

参数字典包含一个参数“category_id”的空条目不可为空的类型'System.Int32' 对于方法 'System.Web.Mvc.ActionResult AddProduct(Int32, System.String, 单，System.String，System.String，系统字符串，系统字符串， System.String, System.String)' 在 '电子商务.Controllers.AdminController'。使参数可选其类型应该是引用类型或可空类型。参数名称：参数

我正在使用一个对话框。

观点

<script type="text/javascript">
        $(function() {
        $("#dialog").dialog({
            bgiframe: true,
            height: 140,
            modal: true,
            autoOpen: false, 
            resizable: false
            })
    });

</script>

<div id="dialog" title="Upload files">
    <% using (Html.BeginForm("Upload", "File", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {%>
            <p><input type="file" id="fileUpload" name="fileUpload" size="23"/> </p>
            <p><input type="submit" value="Upload file" /></p>
        <% } %>
</div>

<p>
    <label for="image_name">image_name:</label>
    <a href="#" onclick="jQuery('#dialog').dialog('open'); return false">Upload File</a>

    <%= Html.ValidationMessage("image_name", "*") %>
</p>

控制器动作

public ActionResult AddProduct(int category_id, string product_name, float product_price, string product_desc, string weight, string image_name, string img_content, string available_qty, string isFeature)
{

    foreach (string inputTagName in Request.Files)
    {
        HttpPostedFileBase file = Request.Files[inputTagName];
        if (file.ContentLength > 0)
        {
            string filePath = Path.Combine(HttpContext.Server.MapPath("../Uploads"), Path.GetFileName(file.FileName));
            string filecontent = Path.Combine(HttpContext.Server.MapPath("../Uploads"), Path.GetFileName(file.ContentType));

            image_name = Path.GetFileName(file.FileName);
            img_content = Path.GetFileName(file.ContentType);

            file.SaveAs(filePath);
        }
    }

    AdminImplementation _adminImplementation = new AdminImplementation();

    Boolean isfeature = Convert .ToBoolean(isFeature);

    if (isfeature)
    {
        isFeature = "Featured";
    }
    else
    {
        isFeature = "NotFeatured";
    }


    int i = _adminImplementation.addproduct(category_id, product_name, product_price, product_desc, weight,image_name ,img_content ,available_qty ,isFeature );

    ViewData["succm"] = "Product added successfully";
    return View();
}

请提出一些有用的答案。

谢谢

丽兹

【问题讨论】：

我们还需要方法签名。
现在我已经解决了您的问题，请提供最初呈现页面的 ViewResult。我需要知道缺失值在哪里。此外，如果您不知道为什么会出现此错误，我建议您访问 www.asp.net/mvc/，因为您似乎不了解 ASP.NET 中 MVC 架构的一些基本元素。

标签： asp.net-mvc upload

【解决方案1】：

在我看来，您没有提供特定 ActionResult 所需的所有参数。 category_id 未提供给 AddProduct。您需要向我们展示您的代码，以便我们找出真正的问题所在。

你怎么称呼那个 ActionResult？

【讨论】：

【解决方案2】：

**UPLOADING IMAGE AND SAVING PATH IN THE DATABASE
________________________________________________________________________________________
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<div>
            <h3> Choose File to Upload in Server </h3>          
           <form action="Recent" method="post" enctype="multipart/form-data">

            <input type="file" name="file" />
            <input type="submit" value="upload" />
            </form>          
        </div>


</body>
</html>
____________________________________________________________________________________________

import java.sql.*;
import java.io.*;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import java.util.Hashtable;
import java.util.List;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.ParameterParser;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;


/**
 * Servlet implementation class Recent
 */
@WebServlet("/Recent")
@MultipartConfig
public class Recent extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Recent() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // TODO Auto-generated method stub
         Sample  s1=new Sample();
         final String UPLOAD_DIRECTORY = "/home/pradeep/Documents/pradeep/WebContent/Images";
         if(ServletFileUpload.isMultipartContent(request)){
                try {
         List<FileItem> multiparts = new 
                            ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);

                    for(FileItem item : multiparts){
                        if(!item.isFormField())
                        {
                            String name = new File(item.getName()).getName();
                            item.write( new File(UPLOAD_DIRECTORY + File.separator + name));
                            String Path= "/home/pradeep/Documents/pradeep/WebContent/Images/" +name;


                          s1.connecting(Path);


                        }
                    }

                        request.setAttribute("message", "File Uploaded Successfully");
                } catch (Exception ex) {
                   request.setAttribute("message", "File Upload Failed due to " + ex);
                }          

            }else{
                request.setAttribute("message",
                                     "Sorry this Servlet only handles file upload request");
            }



                request.getRequestDispatcher("/Result.jsp").forward(request, response);




    }

}
__________________________________________________________________________________________
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import dbconnections.Connections;



public class Sample {
    Connections con=new Connections();

    public void connecting(String Path)
    {
        Connection conn=con.Connect();

        PreparedStatement pst;
        String query="INSERT INTO Student1 (Path) values (?)";
       try {

            pst=conn.prepareStatement(query);
            pst.setString(1,Path);
            pst.executeUpdate();

        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        // TODO Auto-generated method stub
    }


}

【讨论】：