相同的图像调整大小和图像裁剪功能可在Winforms应用程序中使用，而在相同解决方案的Webapi应用程序中则无法使用

Question

Short intro: I have this solution which consists of a Webapi app, Winforms (UI) app, then Xamarin Forms (Android, UWP, iOS).

Now, resize and crop functionality works in Winforms' app. Since I'm using in my Webapi app PerformInitSetup() to init the data, I also wanted to apply here the functionality of thumbnail generation.

These are the methods (which are placed in a helper class of each app):

    public static Image CropImage(Image img, Rectangle cropArea)
    {
        Bitmap bmpImage = new Bitmap(img);
        Bitmap bmpCrop = bmpImage.Clone(cropArea,
        bmpImage.PixelFormat);
        return (Image)(bmpCrop);
    }

    public static Image ResizeImage(Image imgToResize, Size size)
    {
        int sourceWidth = imgToResize.Width;
        int sourceHeight = imgToResize.Height;

        float nPercent = 0;
        float nPercentW = 0;
        float nPercentH = 0;

        nPercentW = ((float)size.Width / (float)sourceWidth);
        nPercentH = ((float)size.Height / (float)sourceHeight);

        if (nPercentH < nPercentW)
            nPercent = nPercentH;
        else
            nPercent = nPercentW;

        int destWidth = (int)(sourceWidth * nPercent);
        int destHeight = (int)(sourceHeight * nPercent);

        Bitmap b = new Bitmap(destWidth, destHeight);
        Graphics g = Graphics.FromImage((Image)b);
        g.InterpolationMode = InterpolationMode.HighQualityBicubic;

        g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
        g.Dispose();

        return (Image)b;
    }

In Winforms app (which does work), here's how a regular image is saved, and then a thumbnail generated based on it:

    private void btnAddImage_Click(object sender, EventArgs e)
    {
        if (openFileDialog.ShowDialog() == DialogResult.OK)
        {
            txtImage.Text = openFileDialog.FileName;
            Image originalImage = Image.FromFile(openFileDialog.FileName);

            MemoryStream ms = new MemoryStream();
            originalImage.Save(ms, ImageFormat.Jpeg);

            lodging.Image = ms.ToArray();


            int resizedImageWidth = Convert.ToInt32(ConfigurationManager.AppSettings["resizedImageWidth"]);
            int resizedImageHeight = Convert.ToInt32(ConfigurationManager.AppSettings["resizedImageHeight"]);
            int croppedImageWidth = Convert.ToInt32(ConfigurationManager.AppSettings["croppedImageWidth"]);
            int croppedImageHeight = Convert.ToInt32(ConfigurationManager.AppSettings["croppedImageHeight"]);

            if(originalImage.Width > resizedImageWidth)
            {
                Image resizedImage = Util.UIHelper.ResizeImage(originalImage, new Size(resizedImageWidth, resizedImageHeight));
                Image croppedImage = resizedImage;

                if(resizedImage.Width >= croppedImageWidth && resizedImage.Height >= croppedImageHeight)
                {
                    int croppedXPos = (resizedImageWidth - croppedImageWidth) / 2;
                    int croppedYPos = (resizedImageHeight - croppedImageHeight) / 2;

                    croppedImage = Util.UIHelper.CropImage(resizedImage, new Rectangle(croppedXPos, croppedYPos, croppedImageWidth, croppedImageHeight));

                    ms = new MemoryStream();
                    croppedImage.Save(ms, ImageFormat.Jpeg);
                    lodging.ImageThumb = ms.ToArray();

                }
            }
        }
    }

So far, so good.

But when I tried to do the same in Webapi app's PerformInitSetup() method, I'm getting an error (find it at the bottom):

// ... other init data

MemoryStream ms1 = new MemoryStream();
Image img1 = Image.FromFile("D:\\Path\\To\\MyImage\\image.jpg");
img1.Save(ms1, ImageFormat.Jpeg);

MemoryStream img1Thumb = GenerateThumbnailImage(img1);

_ctx.LodgingDbSet.Add(new Lodging { Name = "Name Name", ... other attributes ... , Image = ms1.ToArray(), ImageThumb = img1Thumb.ToArray(), CityId = 1, UserId = 2 });

// ... other init data

Within the class InitDB : DropCreateDatabaseIfModelChanges<MyDbContext> , where PerformInitSetup() method is, I have:

    private MemoryStream GenerateThumbnailImage(Image originalImage)
    {
        int resizedImageWidth = Convert.ToInt32(ConfigurationManager.AppSettings["resizedImageWidth"]);
        int resizedImageHeight = Convert.ToInt32(ConfigurationManager.AppSettings["resizedImageHeight"]);
        int croppedImageWidth = Convert.ToInt32(ConfigurationManager.AppSettings["croppedImageWidth"]);
        int croppedImageHeight = Convert.ToInt32(ConfigurationManager.AppSettings["croppedImageHeight"]);

        MemoryStream ms = new MemoryStream();

        if (originalImage.Width > resizedImageWidth)
        {
            Image resizedImage = Util.Helper.ResizeImage(originalImage, new Size(resizedImageWidth, resizedImageHeight));
            Image croppedImage = resizedImage;

            if (resizedImage.Width >= croppedImageWidth && resizedImage.Height >= croppedImageHeight)
            {
                int croppedXPos = (resizedImageWidth - croppedImageWidth) / 2;
                int croppedYPos = (resizedImageHeight - croppedImageHeight) / 2;

                croppedImage = Util.Helper.CropImage(
                    resizedImage,
                    new Rectangle(croppedXPos, croppedYPos, croppedImageWidth, croppedImageHeight)
                    );

                croppedImage.Save(ms, ImageFormat.Jpeg);
            }
        }

        return ms;
    }

I thought it would work. However, something is wrong, but unfortunately, for some reason, breakpoints seem to not be working within this MyDbContext file (explanation thereof would be appreciated!), so I'm getting this error:

{"Message":
"An error has occurred.",
"ExceptionMessage":
    "Parameter is not valid.",
"ExceptionType":"System.ArgumentException",

"StackTrace":
"   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)\r\n
at System.Drawing.Bitmap..ctor(Int32 width, Int32 height)\r\n
at My_API.Util.Helper.ResizeImage(Image imgToResize, Size size) in D:\\Path\\To\\MyApp\\My_API\\Util\\Helper.cs:line 42\r\n
at My_API.DAL.InitDb.GenerateThumbnailImage(Image originalImage) in D:\\Path\\To\\MyApp\\My_API\\DAL\\MyDbContext.cs:line 341\r\n
at My_API.DAL.InitDb.PerformInitSetup(MyDbContext _ctx) in D:\\Path\\To\\MyApp\\My_API\\DAL\\MyDbContext.cs:line 176\r\n
at My_API.DAL.InitDb.Seed(MyDbContext _ctx) in D:\\Path\\To\\MyApp\\My_API\\DAL\\MyDbContext.cs:line 67\r\n
at System.Data.Entity.DropCreateDatabaseIfModelChanges`1.InitializeDatabase(TContext context)\r\n
// ... more stuff follows

It seems like the passed Image object to the above method is not correct. However, IMO, it is the same as in working Winforms app example.

Am I missing something obvious?

Edit: As suggested in a comment, I'm also providing contents of my Web.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <connectionStrings>
    <add name="MyConnString" connectionString="Data Source=(local);Initial Catalog=mycatalog;Integrated Security=SSPI;MultipleActiveResultSets=true" providerName="System.Data.SqlClient" />
  </connectionStrings>
  <appSettings></appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5.2" />
    <httpRuntime targetFramework="4.5.2" />
  </system.web>
  <system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-10.0.0.0" newVersion="10.0.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="mssqllocaldb" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.7.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.7.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>
</configuration>

Answer 1

The most likely cause is that you have not defined these settings in your web.config :

resizedImageWidth
resizedImageHeight
croppedImageWidth
croppedImageHeight