c# - 图片已保存，但不会加载

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Image is saved and shows in Win File Explorer, doesn't load in app or VS

4年前关闭。




我可以选择在应用程序中添加新客户。客户及其ID，名称和徽标存储在数据库中。徽标只是图像文件的字符串(如logo.png)

徽标的添加似乎很好。当我选择一个图像时，它会显示在CustomerAddView中。

添加客户后，CustomerAddView窗口关闭。在数据库中创建了客户，数据库中的徽标值很好。
主窗口中的客户列表将刷新(CustomerListView)。其他客户的徽标工作正常。但是新的客户徽标(添加到AddView窗口中)会发出以下警告:

System.Windows.Data Warning: 6 : 'DynamicValueConverter' converter failed to convert value '../../Media/Images/Logos/testlogo.png' (type 'String'); fallback value will be used, if available. BindingExpression:Path=Logo; DataItem='Customer_5A59789E69DE0B010CE32D4E23A696EDB09551158A85050E8CA80E51475D369B' (HashCode=45868004); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource') IOException:'System.IO.IOException: Kan bron media/images/logos/testlogo.png niet vinden.
   bij MS.Internal.AppModel.ResourcePart.GetStreamCore(FileMode mode, FileAccess access)
   bij System.IO.Packaging.PackagePart.GetStream(FileMode mode, FileAccess access)
   bij System.IO.Packaging.PackWebResponse.CachedResponse.GetResponseStream()
   bij System.IO.Packaging.PackWebResponse.GetResponseStream()
   bij System.IO.Packaging.PackWebResponse.get_ContentType()
   bij System.Windows.Media.Imaging.BitmapDecoder.SetupDecoderFromUriOrStream(Uri uri, Stream stream, BitmapCacheOption cacheOption, Guid& clsId, Boolean& isOriginalWritable, Stream& uriStream, UnmanagedMemoryStream& unmanagedMemoryStream, SafeFileHandle& safeFilehandle)
   bij System.Windows.Media.Imaging.BitmapDecoder.CreateFromUriOrStream(Uri baseUri, Uri uri, Stream stream, BitmapCreateOptions createOptions, BitmapCacheOption cacheOption, RequestCachePolicy uriCachePolicy, Boolean insertInDecoderCache)
   bij System.Windows.Media.Imaging.BitmapFrame.CreateFromUriOrStream(Uri baseUri, Uri uri, Stream stream, BitmapCreateOptions createOptions, BitmapCacheOption cacheOption, RequestCachePolicy uriCachePolicy)
   bij System.Windows.Media.ImageSourceConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   bij MS.Internal.Data.DefaultValueConverter.ConvertHelper(Object o, Type destinationType, DependencyObject targetElement, CultureInfo culture, Boolean isForward)
   bij MS.Internal.Data.TargetDefaultValueConverter.Convert(Object o, Type type, Object parameter, CultureInfo culture)
   bij MS.Internal.Data.DynamicValueConverter.Convert(Object value, Type targetType, Object parameter, CultureInfo culture)
   bij System.Windows.Data.BindingExpression.ConvertHelper(IValueConverter converter, Object value, Type targetType, Object parameter, CultureInfo culture)'
System.Windows.Data Error: 11 : Fallback value 'Default' (type 'String') cannot be converted for use in 'Source' (type 'ImageSource'). BindingExpression:Path=Logo; DataItem='Customer_5A59789E69DE0B010CE32D4E23A696EDB09551158A85050E8CA80E51475D369B' (HashCode=45868004); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource') NullReferenceException:'System.NullReferenceException: De objectverwijzing is niet op een exemplaar van een object ingesteld.
   bij System.Windows.Media.ImageSourceConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   bij System.Windows.Data.BindingExpressionBase.ConvertValue(Object value, DependencyProperty dp, Exception& e)'

我想知道为什么我的徽标图像在文件资源管理器中的指定文件夹中，但没有按应有的方式显示在“客户”列表中。
而且我想知道为什么通过Visual Studio的解决方案资源管理器添加图像时可以正常工作，但是当我通过CustomerAddView(Model)将图像添加到同一文件夹时却不能工作。

以下是用于添加新客户的文件:
CustomerAddView:

<Grid Margin="5">
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="auto" />
            <ColumnDefinition Width="auto" />
            <ColumnDefinition Width="100" />
            <ColumnDefinition Width="100" />
        </Grid.ColumnDefinitions>

        <TextBlock Name="TBCustomerTitle" FontWeight="Bold">Customer name:</TextBlock>
        <TextBlock Grid.Column="1" FontWeight="Bold" Margin="5,0">*</TextBlock>
        <TextBox Name="TBCustomerData" Grid.Column="2" Grid.ColumnSpan="2"
                 Text="{Binding NewCustomer.Name, UpdateSourceTrigger=PropertyChanged}"></TextBox>

        <TextBlock Grid.Row="1" FontWeight="Bold">Customer logo:</TextBlock>
        <Image Grid.Row="1" Grid.Column="2" MaxHeight="100" MaxWidth="100"
               Source="{Binding NewCustomerLogo, UpdateSourceTrigger=PropertyChanged}" />
        <Button Grid.Row="1" Grid.Column="3" Content="Choose logo"
                Command="{Binding SelectLogoCommand}"/>

        <TextBlock Margin="0,10" Grid.Row="2" Grid.ColumnSpan="4">Fields marked with * are required fields.</TextBlock>

        <Button Grid.Row="3" Grid.ColumnSpan="4" Margin="0,50,0,0"
                Command="{Binding AddConfirmCommand}">Add this customer</Button>
    </Grid>

CustomerAddViewModel:

class CustomerAddViewModel : INotifyPropertyChanged
    {
        private RelayCommand addConfirmCommand;
        private RelayCommand selectLogoCommand;
        Image customerLogo;
        string logoDirectory = "../../Media/Images/Logos/";
        DBCustomer dbCustomer = new DBCustomer();

        #region Add Customer
        public ICommand AddConfirmCommand
        {
            get { return addConfirmCommand ?? (addConfirmCommand = new RelayCommand(() => AddConfirmCustomer())); }
        }

        private void AddConfirmCustomer()
        {
            if(newCustomer.Logo != null)
            {
                customerLogo.Save(logoDirectory + newCustomer.Logo);
            }
            else
            {
                newCustomer.Logo = "Default.png";
            }
            if (!dbCustomer.Create(newCustomer))
            {
                return;
            }
            App.Messenger.NotifyColleagues("AddCustomerDone");
        }
        #endregion

        #region Add logo
        public ICommand SelectLogoCommand
        {
            get { return selectLogoCommand ?? (selectLogoCommand = new RelayCommand(() => SelectLogo())); }
        }

        private void SelectLogo()
        {
            OpenFileDialog chooseFile = new OpenFileDialog();
            chooseFile.Title = "Select a logo";
            chooseFile.Filter = "All supported graphics|*.jpg;*.jpeg;*.png|" +
              "JPEG (*.jpg;*.jpeg)|*.jpg;*.jpeg|" +
              "Portable Network Graphic (*.png)|*.png";
            if(chooseFile.ShowDialog() == DialogResult.OK)
            {
                Stream reader = File.OpenRead(chooseFile.FileName);
                customerLogo = System.Drawing.Image.FromStream((Stream)reader);

                MemoryStream finalStream = new MemoryStream();
                customerLogo.Save(finalStream, ImageFormat.Png);

                // translate to image source
                PngBitmapDecoder decoder = new PngBitmapDecoder(finalStream, BitmapCreateOptions.PreservePixelFormat,
                                                    BitmapCacheOption.Default);
                NewCustomerLogo = decoder.Frames[0];
                newCustomer.Logo = newCustomer.Name + ".png";
            }
        }

        private ImageSource newCustomerLogo;
        public ImageSource NewCustomerLogo
        {
            get
            {
                return newCustomerLogo;
            }
            set
            {
                newCustomerLogo = value;
                OnPropertyChanged(new PropertyChangedEventArgs("NewCustomerLogo"));
            }
        }
        #endregion

        private Customer newCustomer = new Customer();
        public Customer NewCustomer
        {
            get { return newCustomer; }
            set { newCustomer = value; OnPropertyChanged(new PropertyChangedEventArgs("NewCustomer")); }
        }

        #region PropertyChanged
        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged(PropertyChangedEventArgs e)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, e);
        }
        #endregion
    }

客户 list 检视

                <ListBox.ItemTemplate>
                <!-- This DataTemplate is used for every Customer object in the ListBox.-->
                <DataTemplate>
                    <Border BorderThickness="2" BorderBrush="Black"
                    Padding="10" Margin="10"
                    Name="CustomerBorder">

                        <Grid Name="ItemGrid">
                            <Grid.RowDefinitions>
                                <RowDefinition/>
                                <RowDefinition/>
                                <RowDefinition/>
                            </Grid.RowDefinitions>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="100" />
                                <ColumnDefinition Width="100" />
                                <ColumnDefinition Width="*"/>
                            </Grid.ColumnDefinitions>

                            <!-- Logo picture -->
                            <Image Grid.Row="0" Grid.Column="0" Grid.RowSpan="3" HorizontalAlignment="Center"
                                   Source="{helpers:ConcatString FrontString=../../Media/Images/Logos/, BindTo={Binding Path=Logo, FallbackValue=Default}}"
                                   Height="{Binding ActualHeight, ElementName=ItemGrid}"/>

                            <!-- Customer name Row-->
                            <TextBlock Grid.Row="0" Grid.Column="1" Margin="10,0,8,0" FontWeight="Bold"
                               Name="CustomerTitle">
                               Customer:
                            </TextBlock>
                            <TextBlock Grid.Row="0" Grid.Column="2"
                               Name="CustomerDataType"
                               Text="{Binding Path=Name}">
                            </TextBlock>

                            <!-- Environment name Row-->
                            <TextBlock Grid.Row="1" Grid.Column="1" Margin="10,0,8,0" FontWeight="Bold" />
                            <TextBlock Grid.Row="2" Grid.Column="1" Margin="10,0,8,0" FontWeight="Bold" />
                        </Grid>
                    </Border>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

编辑:
此屏幕截图可能使我感到困惑。

我通过CustomerAddView(Model)添加了teSTLogo.png，另外三个在VS Solution Explorer中添加了。
如你看到的:

徽标都在同一目录中。

在VS Solution Explorer中仅显示通过VS Solution Explorer添加的徽标。新的没有。

新徽标未显示在CustomerListView中。其他人做。

编辑2:
将图像保存到数据库而不是将文件名另存为字符串可能是更好的主意吗？

最佳答案

MSDN说:

var uri = new System.Uri("ms-appx:///images/logo.png");

关于c# - 图片已保存，但不会加载，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36646929/