Blazor export to excel
Solution 1
I had a similar need and was able to piece together how to do it via javascript from this project: https://github.com/timplourde/dcidr-blazor
Static Utility Service:
public static class ExcelService
{
public static byte[] GenerateExcelWorkbook()
{
var list = new List<UserInfo>()
{
new UserInfo { UserName = "catcher", Age = 18 },
new UserInfo { UserName = "james", Age = 20 },
};
var stream = new MemoryStream();
// ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
using (var package = new ExcelPackage(stream))
{
var workSheet = package.Workbook.Worksheets.Add("Sheet1");
// simple way
workSheet.Cells.LoadFromCollection(list, true);
////// mutual
////workSheet.Row(1).Height = 20;
////workSheet.Row(1).Style.HorizontalAlignment = ExcelHorizontalAlignment.Center;
////workSheet.Row(1).Style.Font.Bold = true;
////workSheet.Cells[1, 1].Value = "No";
////workSheet.Cells[1, 2].Value = "Name";
////workSheet.Cells[1, 3].Value = "Age";
////int recordIndex = 2;
////foreach (var item in list)
////{
//// workSheet.Cells[recordIndex, 1].Value = (recordIndex - 1).ToString();
//// workSheet.Cells[recordIndex, 2].Value = item.UserName;
//// workSheet.Cells[recordIndex, 3].Value = item.Age;
//// recordIndex++;
////}
return package.GetAsByteArray();
}
}
}
public class UserInfo
{
public string UserName { get; set; }
public int Age { get; set; }
}
Create a js
folder with a site.js
file in the wwwroot
folder
function saveAsFile(filename, bytesBase64) {
var link = document.createElement('a');
link.download = filename;
link.href = "data:application/octet-stream;base64," + bytesBase64;
document.body.appendChild(link); // Needed for Firefox
link.click();
document.body.removeChild(link);
}
In your _Host.cshtml file add the following script in the body section
<script src="~/js/site.js"></script>
In your .razor page that you want to export to excel from
@using YOUR_APP_NAME.Services
@inject IJSRuntime js
<Row Class="d-flex px-0 mx-0 mb-1">
<Button Clicked="@DownloadExcelFile" class="p-0 ml-auto mr-2" style="background-color: transparent" title="Download">
<span class="fa fa-file-excel fa-lg m-0" style="color: #008000; background-color: white;" aria-hidden="true"></span>
</Button>
</Row>
@code {
private void DownloadExcelFile()
{
var excelBytes = ExcelService.GenerateExcelWorkbook();
js.InvokeVoidAsync("saveAsFile", $"test_{DateTime.Now.ToString("yyyyMMdd_HHmmss")}.xlsx", Convert.ToBase64String(excelBytes));
}
}
Solution 2
A .razor component is not an HTTP endpoint like an MVC view is. Your return FileResult is not going to trigger a download by the browser.
You will need to create an MVC controller action and redirect the user there, or use JavaScript to invoke the a file save action. You would then need to use the JavaScript Interop to invoke the JS function.
window.msSaveBlob = function (payload, filename) {
const createBlob = data => new Blob([data], { type: "text/csv;charset=utf-8;" });
const buildDownloadLink = (blob, fileName) => {
let link = document.createElement("a");
link.setAttribute("href", URL.createObjectURL(blob));
link.setAttribute("download", fileName);
link.style = "visibility:hidden";
return link;
};
const invokeDownload = link => {
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
};
const isHtmlDownloadAllowed = document.createElement("a").download !== undefined;
const isSaveBlobAllowed = navigator.msSaveBlob;
isSaveBlobAllowed ? navigator.msSaveBlob(createBlob(payload), filename) :
isHtmlDownloadAllowed ? invokeDownload(buildDownloadLink(createBlob(payload), filename)) :
console.log("Feature unsupported");
};
Of course there are also commercial libraries to help with these types of things. Telerik UI for Blazor Document Processing
Adil15
Updated on June 08, 2022Comments
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Adil15 almost 2 years
I am attempting to add an export to excel button on my blazor server side app. So far after combing the internet this is what I have done.
My button
<div class="row text-right"> <div class="col-12 p-3"> <button class="btn btn-outline-success" @onclick="@(() =>DownloadExcel(formValues.Region, formValues.startDate, formValues.endDate))"> Export to Excel <i class="fa fa-file-excel" aria-hidden="true"></i> </button> </div> </div>
My method in my .razor page
public FileResult DownloadExcel(string Region, DateTime StartDate, DateTime EndDate) { FileResult ExcelFile = searchService.ExportToExcel(Region, StartDate, EndDate); return ExcelFile; }
And Finally my logic in my service
public FileResult ExportToExcel(string Region, DateTime StartDate, DateTime EndDate) { var queryable = context.AuditCardPinrecords.Where(s => Region == s.RegionRecordId) .Where(s => s.AuditComplete == true) .Where(s => s.DateTime >= StartDate && s.DateTime <= EndDate).AsQueryable(); var stream = new MemoryStream(); using (var package = new ExcelPackage(stream)) { var workSheet = package.Workbook.Worksheets.Add("Sheet1"); workSheet.Cells.LoadFromCollection(queryable, true); package.Save(); } string excelName = $"AuditPinRecords-{DateTime.Now.ToString("yyyyMMddHHmmssfff")}.xlsx"; return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", excelName); }
My expected result is to download the excel file. Unfortunately nothing happens on button click. Any advice would be greatly appreciated. Thanks!
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mason about 4 yearsI don't think you can just return a FileResult and have it automatically be given to the user. You might consider just having a link that points to an MVC endpoint so that the user can download it directly from the server.
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David Hicks over 3 yearsGreat step-by-step instructions. Spent about 7 hours yesterday trying to figure this out, but it works now. Thank you Brent!