Merge pull request #2169 from TechnologyEnhancedLearning/Develop/Fixes/TD-2865-Improve-error-messages-when-bulk-upload-Excel-file-doesn't-contain-correct-worksheet_

TD-2865: Invalid file format validation not working issue fixed.

Author: kevwhitt-hee

DigitalLearningSolutions.Web/Controllers/TrackingSystem/Delegates/BulkUploadController.cs

@@ -81,25 +81,22 @@ public IActionResult StartUpload(UploadDelegatesViewModel model)
         {
             int MaxBulkUploadRows = GetMaxBulkUploadRowsLimit();
             model.MaxBulkUploadRows = MaxBulkUploadRows;
-            if (model.DelegatesFile != null)
+            if (!ModelState.IsValid)
             {
-                var workbook = new XLWorkbook(model.DelegatesFile.OpenReadStream());
-                if (!workbook.Worksheets.Contains(DelegateDownloadFileService.DelegatesSheetName))
-                {
-                    ModelState.AddModelError("MaxBulkUploadRows", CommonValidationErrorMessages.InvalidBulkUploadExcelFile);
-                    return View("StartUpload", model);
-                }
-                int ExcelRowsCount = delegateUploadFileService.GetBulkUploadExcelRowCount(model.DelegatesFile);
-                if (ExcelRowsCount > MaxBulkUploadRows)
-                {
-                    ModelState.AddModelError("MaxBulkUploadRows", string.Format(CommonValidationErrorMessages.MaxBulkUploadRowsLimit, MaxBulkUploadRows));
-                }
+                return View("StartUpload", model);
             }
-            if (!ModelState.IsValid)
+            var workbook = new XLWorkbook(model.DelegatesFile.OpenReadStream());
+            if (!workbook.Worksheets.Contains(DelegateDownloadFileService.DelegatesSheetName))
             {
+                ModelState.AddModelError("MaxBulkUploadRows", CommonValidationErrorMessages.InvalidBulkUploadExcelFile);
+                return View("StartUpload", model);
+            }
+            int ExcelRowsCount = delegateUploadFileService.GetBulkUploadExcelRowCount(model.DelegatesFile);
+            if (ExcelRowsCount > MaxBulkUploadRows)
+            {
+                ModelState.AddModelError("MaxBulkUploadRows", string.Format(CommonValidationErrorMessages.MaxBulkUploadRowsLimit, MaxBulkUploadRows));
                 return View("StartUpload", model);
             }
-
             try
             {
                 var results = delegateUploadFileService.ProcessDelegatesFile(