change datepicker dialog language

frontend/src/app/ntt-gantt/ntt-gantt.component.ts

@@ -22,6 +22,8 @@ import { SavePresetUnderDialogComponent } from '../save-preset-under-dialog/save
 import { Location } from '@angular/common';
 import { environment } from 'src/environments/environment';
 import { GanttModule, ResizeService } from '@syncfusion/ej2-angular-gantt';
+import { DateAdapter } from '@angular/material/core';
+import { MAT_DATE_LOCALE } from '@angular/material/core';
 
 
 export const MY_DATE_FORMATS = {
@@ -197,7 +199,7 @@ export class NttGanttComponent implements OnInit {
    * @param dataService injects the dataService for data management and backend communication
    * @param matDialog injects the matDialog
    */
-  constructor(public languageService: LanguageService, public dataService: DataService, public matDialog: MatDialog, private _snackBar: MatSnackBar, public errorService: ErrorService, private location: Location) {
+  constructor(public languageService: LanguageService, public dataService: DataService, public matDialog: MatDialog, private _snackBar: MatSnackBar, public errorService: ErrorService, private location: Location, private dateAdapter: DateAdapter<Date>) {
     this.initLanguge(true);
   }
 
@@ -684,9 +686,18 @@ export class NttGanttComponent implements OnInit {
   */
   public languageChange(args: any) {
     this.languageService.languageChange(args.value),
-      this.initLanguge();
+    this.initLanguge();
     this.plantimeComponent.changeLanguage();
     this.editUserPreferences();
+    this.updateDatePickerLocale();
+  }
+
+  private updateDatePickerLocale() {
+    if (this.languageService.language === 'DE') {
+      this.dateAdapter.setLocale('de');
+    } else {
+      this.dateAdapter.setLocale('en');
+    }
   }
 
   /**
@@ -699,11 +710,12 @@ export class NttGanttComponent implements OnInit {
     if (this.languageService.language == 'DE') {
       this.scalars = ['Monat', 'Jahr'];
       this.selectedScalar = 'Monat';
+      this.dateAdapter.setLocale('de');
     }
     else {
       this.scalars = ['Month', 'Year'];
       this.selectedScalar = 'Month';
-
+      this.dateAdapter.setLocale('en');
     }
     this.columns = this.languageService.getColumns();
     if (!initial) {