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V25.1
  • DxFileInput.SelectedFilesChanged Event

    Fires when the file list changes.

    Namespace: DevExpress.Blazor

    Assembly: DevExpress.Blazor.v25.1.dll

    NuGet Package: DevExpress.Blazor

    Declaration

    [Parameter]
    public EventCallback<IEnumerable<UploadFileInfo>> SelectedFilesChanged { get; set; }

    Parameters

    Type Description
    IEnumerable<UploadFileInfo>

    A collection of objects that store information about files in the file list.

    Remarks

    Once a user selects files in the Open dialog or drags files onto a drop zone, the File Input component adds these files to the file list. The file list indicates each file’s upload status and displays upload, cancel, reload, and remove buttons.

    The SelectedFilesChanged event occurs when the collection of files displayed in the file list changes (even when the file list is hidden). Handle this event to respond to collection changes or access selected files. Call the following methods to manage files in code:

    Start Upload Cancel Upload Restart Canceled Upload Remove Files from List
    One File UploadFile CancelFileUpload ReloadFile RemoveFile
    Multiple Files UploadFiles CancelFilesUpload ReloadFiles RemoveFiles
    All Files UploadAllFiles CancelAllFilesUpload ReloadAllFiles RemoveAllFiles

    The following example applies CSS classes to the File Input component and its container when the file list contains at least one file:

    Selected Files Changed

    <div class="upload-container">
        <div style="@(SelectedFilesCount > 0 ? "display: none" : string.Empty)">
            <span class="drop-file-icon mb-3"></span>
            <span class="mb-3">Click the Select Files button to select a file</span>
        </div>
        <DxFileInput SelectedFilesChanged="@SelectedFilesChanged"
                     FilesUploading="OnFilesUploading"
                     CssClass="@(SelectedFilesCount > 0 ? "w-100" : string.Empty)">
        </DxFileInput>
    </div>
    
    @code {
        int SelectedFilesCount { get; set; }
    
        protected void SelectedFilesChanged(IEnumerable<UploadFileInfo> files) {
            SelectedFilesCount = files.ToList().Count;
            InvokeAsync(StateHasChanged);
        }
    
        protected async Task OnFilesUploading(FilesUploadingEventArgs args) {
            foreach (var file in args.Files) {
                /* The following code is intended for demonstration purposes only.
                Do not read a stream directly in memory to avoid performance and security-related issues. */
                using var stream = new System.IO.MemoryStream();
                await file.OpenReadStream(file.Size).CopyToAsync(stream);
            }
        }
    }
    

    You can enable the AllowMultiFileUpload property to allow users to add multiple files to the file list simultaneously. The MaxFileCount property specifies the maximum file list size.

    Run Demo: File Input - Multiple File Selection

    See Also