public async Task ReadFile()
{
Output = string.Empty;
this.StateHasChanged();
var files = await fileReaderService.CreateReference(inputElement).EnumerateFilesAsync();
var isCustomGetLengthMethodInitialized = await CurrentJSRuntime.InvokeAsync <bool>("window.hasOwnProperty", "customGetLengthMethod");
if (!isCustomGetLengthMethodInitialized)
{
await WriteLine("Defining custom method 'customGetLengthMethod'");
await CurrentJSRuntime.InvokeVoidAsync("eval",
@"window.customGetLengthMethod = (jsFileFromDotNet) => {
return jsFileFromDotNet.size;
};");
}
if (!files.Any())
{
await WriteLine("No file selected");
}
foreach (var file in files)
{
var jsFile = await file.GetJSObjectReferenceAsync();
await using (jsFile)
{
// get length manually using a custom method
var length = await this.CurrentJSRuntime.InvokeAsync <long>("customGetLengthMethod", jsFile);
await WriteLine($"Length from customGetLengthMethod: {length}");
}
}
}
private async Task <int> ReadFileMarshalledAsync(
int fileRef, byte[] buffer, long position, int count,
CancellationToken cancellationToken)
{
var taskCompletionSource = new TaskCompletionSource <ReadFileMarshalledAsyncCallbackParams>();
cancellationToken.Register(() => taskCompletionSource.TrySetCanceled());
var callBackId = Guid.NewGuid().ToString("N");
readFileMarshalledAsyncCalls[callBackId] = taskCompletionSource;
var startCallBack = await CurrentJSRuntime.InvokeAsync <long>(
$"FileReaderComponent.ReadFileMarshalledAsync",
new { position, count, callBackId, fileRef });
ReadFileMarshalledAsyncCallbackParams longResult;
try
{
longResult = await taskCompletionSource.Task;
}
catch (Exception e)
{
var x = e;
throw;
}
var bytesRead = 0;
if (!string.IsNullOrEmpty(longResult.Data?.Trim()))
{
var byteResult = Convert.FromBase64String(longResult.Data);
bytesRead = byteResult.Length;
Array.Copy(byteResult, buffer, bytesRead);
}
return(bytesRead);
}
private Task <bool> DisposeStream(int fileRef)
{
return(CurrentJSRuntime.InvokeAsync <bool>($"FileReaderComponent.Dispose", fileRef));
}
private async Task <int> OpenReadAsync(ElementRef elementReference, int fileIndex)
{
return((int)await CurrentJSRuntime.InvokeAsync <long>($"FileReaderComponent.OpenRead", elementReference, fileIndex));
}
public async Task <FileInfo> GetFileInfoFromReference(int fileRef)
{
return(Json.Deserialize <FileInfo>(await CurrentJSRuntime.InvokeAsync <string>($"FileReaderComponent.GetFileInfoFromReference", fileRef)));
}
public async Task <FileInfo> GetFileInfoFromElement(ElementRef elementReference, int index)
{
return(Json.Deserialize <FileInfo>(await CurrentJSRuntime.InvokeAsync <string>($"FileReaderComponent.GetFileInfoFromElement", elementReference, index)));
}
public async Task <int> GetFileCount(ElementRef elementReference)
{
return((int)await CurrentJSRuntime.InvokeAsync <long>($"FileReaderComponent.GetFileCount", elementReference));
}
public async Task <int> ClearValue(ElementRef elementReference)
{
return((int)await CurrentJSRuntime.InvokeAsync <long>($"FileReaderComponent.ClearValue", elementReference));
}