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Asp.Net Core : Beispiel Code  Foto Upload und Resize Foto

 

Dieses C# Code Beispiel zeigt

Wie man Fotos in Asp.Net Core hochladen kann und nach dem Hochladen automatisch anpassen kann

 

In Asp.Net Core 2 MVC

 

 

Video Anleitung unter https://www.youtube.com/watch?v=h1kqeBpexS4&feature=youtu.be

 

 

 

Image View

@{

    Layout = null;

}

 

<!DOCTYPE html>

 

<html>

<head>

    <meta name="viewport" content="width=device-width" />

    <title>Upload_Image</title>

</head>

<body>

    <br /><br />

    <span style="margin-top:10px;"> Upload Your Profil Image:</span>

    <br />

    <form asp-controller="Image" asp-action="Upload_User_Profil_Image" method="post"

          enctype="multipart/form-data">

 

        <input type="file" name="uploaded_File" />

        <br />

        <button type="submit" style="">Upload</button>

    </form>

 

    <br />

    @if (ViewData["FileResized_40"] != null)

    {

        <br />

        <span>Resized 40</span>

        <img src="@ViewData["FileResized_40"]" alt="Uploaded Image" />

        <br />

    }

 

    @if (ViewData["FileResized_80"] != null)

    {

        <br />

        <span>Resized 80</span>

        <img src="@ViewData["FileResized_80"]" alt="Uploaded Image" />

        <br />

    }

 

    @if (ViewData["FileResized_120"] != null)

    {

        <br />

        <span>Resized 120</span>

        <img src="@ViewData["FileResized_120"]" alt="Uploaded Image" />

        <br />

    }

 

    @if (ViewData["FileResized_240"] != null)

    {

        <br />

        <span>Resized 240</span>

        <img src="@ViewData["FileResized_240"]" alt="Uploaded Image" />

        <br />

    }

 

    @if (ViewData["FileResized_400"] != null)

    {

        <br />

        <span>Resized 400</span>

        <img src="@ViewData["FileResized_400"]" alt="Uploaded Image" />

        <br />

    }

 

 

    @if (ViewData["FileUploaded"] != null)

    {

        <br />

        <span>Original Upload</span>

        <img src="@ViewData["FileUploaded"]" alt="Uploaded Image" />

        <br />

    }

 

    @if (ViewData["Error"] != null)

    {

        <label>Error= @ViewData["Error"]</label>

    }

 

    <br />

</body>

</html>

 

 

 

Controller Code in C#

Image Controller Asp.Net Core MVC

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using System.IO;                    //*Directory copy Files

using Microsoft.AspNetCore.Http;    //*IFormFile

using Microsoft.AspNetCore.Mvc;

using Microsoft.AspNetCore.Hosting; //*get RootPath

using System.Drawing;               //CoreCompat Image handling

using System.Drawing.Drawing2D;     //CoreCompat Image handling

using System.Drawing.Imaging;       //CoreCompat Image handling

using IWois_Core.Data;              //ApplicationDbContext Database connection

using Microsoft.AspNetCore.Authorization;   //Identity: Register,Login

using Microsoft.AspNetCore.Authentication;  //Identity: Register,Login

using Microsoft.AspNetCore.Identity;        //Identity: Register,Login

 

namespace IWois_Core.Controllers

{

    public class ImageController : Controller

    {

        private readonly ApplicationDbContext _context;

        private readonly IHostingEnvironment _appEnvironment;

       

        public ImageController(ApplicationDbContext context, IHostingEnvironment appEnvironment)

        {

            //----< Init: Controller >----

            _context = context;

            _appEnvironment = appEnvironment;           

            //----</ Init: Controller >----

        }

 

 

        [Authorize]

        [HttpGet] //1.Load

        public IActionResult Upload_User_Profil_Image()

        {

            //--< Upload Form >--

            return View();

            //--</ Upload Form >--

        }

 

        [Authorize]

        [HttpPost] //Postback

        public async Task<IActionResult> Upload_User_Profil_Image(IFormFile uploaded_File)

        {

            //--------< Upload_ImageFile() >--------

            string sResult = "";

 

 

            //< check >

            if (uploaded_File == null || uploaded_File.Length == 0)

            {

                ViewData["Error"] = "Error:file not selected";

                return View(ViewData);

            }

 

            if (uploaded_File.ContentType.IndexOf("image", StringComparison.OrdinalIgnoreCase) < 0)

            {

                ViewData["Error"] = "Error:This file is not an image";

                return View(ViewData);

            }

            //</ check >

 

            //--< Get User ID >--

            //internal referenz-Number for tracking in tables

            long IDUser = await Common.ExtensionMethods.getIDUser_Number(this.User, _context);

            //--</ Get User ID >--

 

            //< init >

            string sImage_Folder = "User_Images";

            string sTarget_Filename = "User_Image_" + IDUser + ".jpg";

            //</ init >

 

            //< get Path >

            string sPath_WebRoot = _appEnvironment.WebRootPath;

            string sPath_of_Target_Folder = sPath_WebRoot + "\\User_Files\\" + sImage_Folder + "\\";

            string sFile_Target_Original = sPath_of_Target_Folder + "\\Original\\" + sTarget_Filename;

            //string sImage_Filename_Original = sPath_of_Target_Folder + uploaded_File.FileName;

            //</ get Path >

 

            //< Copy File to Target >

            using (var stream = new FileStream(sFile_Target_Original, FileMode.Create))

            {

                await uploaded_File.CopyToAsync(stream);

            }

            //</ Copy File to Target >

 

            //< resize >

            Image_resize(sFile_Target_Original, sPath_of_Target_Folder + "\\40\\" + sTarget_Filename, 40);

            Image_resize(sFile_Target_Original, sPath_of_Target_Folder + "\\80\\" + sTarget_Filename, 80);

            Image_resize(sFile_Target_Original, sPath_of_Target_Folder + "\\120\\" + sTarget_Filename, 120);

            Image_resize(sFile_Target_Original, sPath_of_Target_Folder + "\\240\\" + sTarget_Filename, 240);

            Image_resize(sFile_Target_Original, sPath_of_Target_Folder + "\\400\\" + sTarget_Filename, 400);

            //</ resize >

 

            //string sResult= await Safe_Uploaded_Image(ref uploaded_File, "User_Images");

 

 

            //< output >

            ViewData["FileUploaded"] = "/User_Files/User_Images/Original/" + sTarget_Filename;

            ViewData["FileResized_40"] = "/User_Files/User_Images/40/" + sTarget_Filename;

            ViewData["FileResized_80"] = "/User_Files/User_Images/80/" + sTarget_Filename;

            ViewData["FileResized_120"] = "/User_Files/User_Images/120/" + sTarget_Filename;

            ViewData["FileResized_240"] = "/User_Files/User_Images/240/" + sTarget_Filename;

            ViewData["FileResized_400"] = "/User_Files/User_Images/400/" + sTarget_Filename;

            return View();

            //</ output >

            //--------</ Upload_ImageFile() >--------

        }

 

 

        private void Image_resize(string input_Image_Path, string output_Image_Path,int new_Width)

        {

            //---------------< Image_resize() >---------------

            //*Resizes an Image in Asp.Net MVC Core 2

            //*Using Nuget CoreCompat.System.Drawing

            //using System.IO

            //using System.Drawing;             //CoreCompat

            //using System.Drawing.Drawing2D;   //CoreCompat

            //using System.Drawing.Imaging;     //CoreCompat

 

            const long quality = 50L;

            Bitmap source_Bitmap = new Bitmap(input_Image_Path);

           

            double dblWidth_origial = source_Bitmap.Width;

            double dblHeigth_origial = source_Bitmap.Height;

            double relation_heigth_width = dblHeigth_origial / dblWidth_origial;

            int new_Height = (int)(new_Width * relation_heigth_width);

 

            //< create Empty Drawarea >

            var new_DrawArea = new Bitmap(new_Width, new_Height);

            //</ create Empty Drawarea >

 

            using (var graphic_of_DrawArea = Graphics.FromImage(new_DrawArea))

            {

                //< setup >

                graphic_of_DrawArea.CompositingQuality = CompositingQuality.HighSpeed;

                graphic_of_DrawArea.InterpolationMode = InterpolationMode.HighQualityBicubic;

                graphic_of_DrawArea.CompositingMode = CompositingMode.SourceCopy;

                //</ setup >

 

                //< draw into placeholder >

                //*imports the image into the drawarea

                graphic_of_DrawArea.DrawImage(source_Bitmap, 0, 0, new_Width, new_Height);

                //</ draw into placeholder >

 

                //--< Output as .Jpg >--

                using (var output = System.IO.File.Open(output_Image_Path, FileMode.Create))

                {

                    //< setup jpg >

                    var qualityParamId = Encoder.Quality;

                    var encoderParameters = new EncoderParameters(1);

                    encoderParameters.Param[0] = new EncoderParameter(qualityParamId, quality);

                    //</ setup jpg >

 

                    //< save Bitmap as Jpg >

                    var codec = ImageCodecInfo.GetImageDecoders().FirstOrDefault(c => c.FormatID == ImageFormat.Jpeg.Guid);

                    new_DrawArea.Save(output, codec, encoderParameters);

                    //resized_Bitmap.Dispose();

                    output.Close();

                    //</ save Bitmap as Jpg >

                }

                //--</ Output as .Jpg >--

                graphic_of_DrawArea.Dispose();

            }

            source_Bitmap.Dispose();

            //---------------</ Image_resize() >---------------

        }

 

    }

}

 

Mobile

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