Blazorise FileEdit component

The FileEdit component is a specialized input that provides a clean interface for selecting files.

Customized, cross-browser consistent, file input control that supports single file and multiple files upload.

Examples

Single file (default)

On single file mode, when file is selected or user does not cancel Browse dialog, Changed event will be raised. The return value will be a FileChangedEventArgs that will contain only one item in the Files property.
<Field>
    <FileEdit Changed="@OnChanged" />
</Field>
@code {
    Task OnChanged( FileChangedEventArgs e )
    {
        return Task.CompletedTask;
    }
}

Multiple files

Multiple file uploading is supported by enabling Multiple attribute to component. In this case Files property of FileChangedEventArgs can contain multiple files.
<Field>
    <FileEdit Changed="@OnChanged" Multiple />
</Field>
@code {
    Task OnChanged( FileChangedEventArgs e )
    {
        return Task.CompletedTask;
    }
}

Directories

Directory uploading is supported by enabling Directory attribute to component. In this case Files property of FileChangedEventArgs can contain multiple files within a directory.
<Field>
    <FileEdit Changed="@OnChanged" Directory />
</Field>
@code {
    Task OnChanged( FileChangedEventArgs e )
    {
        return Task.CompletedTask;
    }
}

Multiple Directories

Multiple Directory uploading is supported by enabling Directory and Multiple attribute to component. In this case Files property of FileChangedEventArgs can contain multiple files within a directory.
<Field>
    <FileEdit Changed="@OnChanged" Directory Multiple />
</Field>
@code {
    Task OnChanged( FileChangedEventArgs e )
    {
        return Task.CompletedTask;
    }
}

Limiting to certain file types

You can limit the file types by setting the Filter attribute to a string containing the allowed file type(s). To specify more than one type, separate the values with a comma.

To accept any file type, leave Filter as null (default).

<!-- Accept all image formats by IANA media type wildcard-->
<Field>
    <FileEdit Filter="image/*" />
</Field>

<!-- Accept specific image formats by IANA type -->
<Field>
    <FileEdit Filter="image/jpeg, image/png, image/gif" />
</Field>

<!-- Accept specific image formats by extension -->
<Field>
    <FileEdit Filter=".jpg, .png, .gif" />
</Field>

Events

Changed

This is the main event that will be called every time a user selects a single or multiple files. Depending on the mode in which the FileEdit currently operates. In all cases the event argument is the same. Only difference is that Files array will contain single or multiple items.

Written

This event will be called on every buffer of data that has being written to the destination stream. It is directly related to the MaxMessageSize attribute found on FileEdit component and will contain the information about currently processed file, it’s offset and data array.

Progressed

Similar to the Written, this event will also be called while file is writing to the destination stream but it will contain only the progress and percentage on how much the file is being uploaded.

Started

This event will be called each time one of the selected file(s) has started the upload process.

Ended

This event is fired after the file has ended the upload process. If there was no error it will have Success property set to true.

Examples

WriteToStreamAsync

In this example you can see the usage of all events, including the Written and Progressed. For your own use case you can just focus on Changed event.
@using System.IO

<Field>
    <FileEdit Changed="@OnChanged" Written="@OnWritten" Progressed="@OnProgressed" />
</Field>
@code {
    string fileContent;

    async Task OnChanged( FileChangedEventArgs e )
    {
        try
        {
            foreach ( var file in e.Files )
            {
                // A stream is going to be the destination stream we're writing to.
                using ( var stream = new MemoryStream() )
                {
                    // Here we're telling the FileEdit where to write the upload result
                    await file.WriteToStreamAsync( stream );

                    // Once we reach this line it means the file is fully uploaded.
                    // In this case we're going to offset to the beginning of file
                    // so we can read it.
                    stream.Seek( 0, SeekOrigin.Begin );

                    // Use the stream reader to read the content of uploaded file,
                    // in this case we can assume it is a textual file.
                    using ( var reader = new StreamReader( stream ) )
                    {
                        fileContent = await reader.ReadToEndAsync();
                    }
                }
            }
        }
        catch ( Exception exc )
        {
            Console.WriteLine( exc.Message );
        }
        finally
        {
            this.StateHasChanged();
        }
    }

    void OnWritten( FileWrittenEventArgs e )
    {
        Console.WriteLine( $"File: {e.File.Name} Position: {e.Position} Data: {Convert.ToBase64String( e.Data )}" );
    }

    void OnProgressed( FileProgressedEventArgs e )
    {
        Console.WriteLine( $"File: {e.File.Name} Progress: {e.Percentage}" );
    }
}

OpenReadStream

Using OpenReadStream on the file you can process the file as it is streamed from the browser to your code, this is mirrors the API found in ASP.NET Core Input File component, for example
@using System.IO

<Field>
    <FileEdit Changed="@OnChanged" Written="@OnWritten" Progressed="@OnProgressed" />
</Field>
@code {
    async Task OnChanged( FileChangedEventArgs e )
    {
        try
        {
            var file = e.Files.FirstOrDefault();
            if ( file == null )
            {
                return;
            }

            using ( MemoryStream result = new MemoryStream() )
            {
                await file.OpenReadStream( long.MaxValue ).CopyToAsync( result );
            }
        }
        catch ( Exception exc )
        {
            Console.WriteLine( exc.Message );
        }
        finally
        {
            this.StateHasChanged();
        }
    }

    void OnWritten( FileWrittenEventArgs e )
    {
        Console.WriteLine( $"File: {e.File.Name} Position: {e.Position} Data: {Convert.ToBase64String( e.Data )}" );
    }

    void OnProgressed( FileProgressedEventArgs e )
    {
        Console.WriteLine( $"File: {e.File.Name} Progress: {e.Percentage}" );
    }
}

Reset

By default after each file upload has finished, file input will automatically reset to it’s initial state. If you want this behavior disabled and control it manually you need to first set AutoReset to false. After that you can call Reset() every time you want the file input to be reset.
<Field>
    <FileEdit @ref="@fileEdit" AutoReset="false" Changed="@OnChanged" />
</Field>
<Field>
    <Button Color="Color.Primary" Clicked="Reset">Reset</Button>
</Field>
@code {
    FileEdit fileEdit;

    Task OnChanged(FileChangedEventArgs e)
    {
        return Task.CompletedTask;
    }

    Task Reset()
    {
        return fileEdit.Reset().AsTask();
    }
}

Show Picker

If you want to show the default picker that comes with the file input element you can make it by using the ShowPicker() function.

Note: Keep in mind that not all browser will support the ShowPicker() function.

<Field>
    <Button Color="Color.Primary" Clicked="@(()=>fileEditRef.ShowPicker())">
        Show Picker
    </Button>
</Field>
<Field>
    <FileEdit @ref="@fileEditRef" />
</Field>
@code {
    FileEdit fileEditRef;
}

API

Parameters

Parameter Description TypeDefault
Autofocus

Set's the focus to the component after the rendering is done.

boolfalse
AutoReset

If true file input will be automatically reset after it has being uploaded.

booltrue
BrowseButtonLocalizer

Function used to handle custom localization that will override a default Localization.ITextLocalizer.

TextLocalizerHandlernull
ChildContent

Specifies the content to be rendered inside this FileEdit.

RenderFragmentnull
Directory

Gets or Sets whether file picker should upload directories.

boolfalse
Disabled

Add the disabled boolean attribute on an input to prevent user interactions and make it appear lighter.

boolfalse
DisableProgressReport

Gets or sets whether report progress should be disabled. By enabling this setting, Progressed and Written callbacks won't be called. Internal file progress won't be tracked.

This setting can speed up file transfer considerably.

boolfalse
Feedback

Placeholder for validation messages.

RenderFragmentnull
Filter

Specifies the types of files that the input accepts. See w3schools.com.

string
MaxChunkSize

Gets or sets the max chunk size when uploading the file. Take note that if you're using FileEdit.OpenReadStream(FileEntry,CancellationToken) you're provided with a stream and should configure the chunk size when handling with the stream.

Remarks

See docs.microsoft.com.

int20 * 1024
MaxFileSize

Maximum file size in bytes, checked before starting upload (note: never trust client, always check file size at server-side). Defaults to long.MaxValue.

longlong.MaxValue
Multiple

Enables the multiple file selection.

boolfalse
Placeholder

Sets the placeholder for the empty file input.

string
ReadOnly

Add the readonly boolean attribute on an input to prevent modification of the input’s value.

boolfalse
SegmentFetchTimeout

Gets or sets the Segment Fetch Timeout when uploading the file.

TimeSpanTimeSpan.FromMinutes( 1 )
Size

Sets the size of the input control.

Size?null
TabIndex

If defined, indicates that its element can be focused and can participates in sequential keyboard navigation.

int?null

Events

Event Description Type
Blur

The blur event fires when an element has lost focus.

EventCallback<FocusEventArgs>
Changed

Occurs every time the selected file has changed, including when the reset operation is executed.

EventCallback<FileChangedEventArgs>
CustomValidationValue

Used to provide custom validation value on which the validation will be processed with the Validation.Validator handler.

Remarks

Should be used carefully as it's only meant for some special cases when input is used in a wrapper component, like Autocomplete or SelectList.

Func<TValue>
Ended

Occurs when an individual file upload has ended.

EventCallback<FileEndedEventArgs>
FocusIn

Occurs when the input box gains focus.

EventCallback<FocusEventArgs>
FocusOut

Occurs when the input box loses focus.

EventCallback<FocusEventArgs>
KeyDown

Occurs when a key is pressed down while the control has focus.

EventCallback<KeyboardEventArgs>
KeyPress

Occurs when a key is pressed while the control has focus.

EventCallback<KeyboardEventArgs>
KeyUp

Occurs when a key is released while the control has focus.

EventCallback<KeyboardEventArgs>
OnFocus

Occurs when the input box gains or loses focus.

EventCallback<FocusEventArgs>
Progressed

Notifies the progress of file being written to the destination stream.

EventCallback<FileProgressedEventArgs>
Started

Occurs when an individual file upload has started.

EventCallback<FileStartedEventArgs>
Written

Occurs every time the part of file has being written to the destination stream.

EventCallback<FileWrittenEventArgs>

Methods

Method DescriptionReturnParameters
NotifyChange Notifies the component that file input value has changed. TaskFileEntry[] files
UpdateFileStartedAsync Notifies the component that file upload is about to start. TaskIFileEntry fileEntry
UpdateFileEndedAsync Notifies the component that file upload has ended. TaskIFileEntry fileEntry, bool success, FileInvalidReason fileInvalidReason
UpdateFileWrittenAsync Updates component with the latest file data. TaskIFileEntry fileEntry, long position, byte[] data
UpdateFileProgressAsync Updated the component with the latest upload progress. TaskIFileEntry fileEntry, long progressProgress
WriteToStreamAsync Writes the file data to the target stream. TaskFileEntry fileEntry, Stream stream, CancellationToken cancellationToken
OpenReadStream Opens the stream for reading the uploaded file. StreamFileEntry fileEntry, CancellationToken cancellationToken
Reset Manually resets the input file value. ValueTask
RemoveFile Removes a file from the current file selection. ValueTaskint fileId
ShowPicker Show a browser picker for the file input. Task
Focus Sets the focus on the underline element. Taskbool scrollToElement
Revalidate Forces the Validation (if any is used) to re-validate with the new custom or internal value. Task
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