chore(*): fix an error in filtering dev demo

Author: DiyanDimitrov

src/app/grid-filtering/grid-filtering.sample.html

@@ -3,7 +3,7 @@
         Demonstrates grid's filtering functionality.
     </app-page-header>
 
-    
+
 
     <div class="sample-content">
         <div class="sample-column">
@@ -18,17 +18,18 @@
                 [allowFiltering]="true"
                 [filterMode]="'excelStyleFilter'"
                 [allowAdvancedFiltering]="true"
+                [advancedFilteringExpressionsTree]="advancedFilteringTree"
                 [rowSelectable]="true"
                 [paging]="false"
                 [width]="'980px'"
-                [height]="'600px'" 
+                [height]="'600px'"
                 [showToolbar]="true"
-                [columnHiding]="true" 
+                [columnHiding]="true"
                 [columnPinning]="true"
-                [exportExcel]="true" 
-                [exportCsv]="true" 
+                [exportExcel]="true"
+                [exportCsv]="true"
                 exportText="Export"
-                exportExcelText="Export to Excel" 
+                exportExcelText="Export to Excel"
                 exportCsvText="Export to CSV">
                 <igx-column *ngFor="let c of columns" [field]="c.field"
                                                     [header]="c.header"

src/app/grid-filtering/grid-filtering.sample.ts

@@ -8,52 +8,21 @@ import { IgxGridComponent, FilteringExpressionsTree, IgxStringFilteringOperand,
     styleUrls: ['grid-filtering.sample.css'],
     templateUrl: 'grid-filtering.sample.html'
 })
-export class GridFilteringComponent implements OnInit, AfterViewInit {
+export class GridFilteringComponent implements OnInit {
 
     public data: Array<any>;
     public columns: Array<any>;
     public displayDensities;
     public filterModes;
     public density = 'comfortable';
+    public advancedFilteringTree: FilteringExpressionsTree;
 
     @ViewChild('grid1', { static: true })
     public grid1: IgxGridComponent;
 
     @ViewChild('applyChangesCheckbox', { static: true })
     public applyChangesCheckbox: IgxCheckboxComponent;
 
-    ngAfterViewInit(): void {
-        const tree = new FilteringExpressionsTree(FilteringLogic.And);
-        tree.filteringOperands.push({
-            fieldName: 'ID',
-            condition: IgxStringFilteringOperand.instance().condition('contains'),
-            searchVal: 'a',
-            ignoreCase: true
-        });
-        const orTree = new FilteringExpressionsTree(FilteringLogic.Or);
-        orTree.filteringOperands.push({
-            fieldName: 'ID',
-            condition: IgxStringFilteringOperand.instance().condition('contains'),
-            searchVal: 'b',
-            ignoreCase: true
-        });
-        orTree.filteringOperands.push({
-            fieldName: 'CompanyName',
-            condition: IgxStringFilteringOperand.instance().condition('contains'),
-            searchVal: 'c',
-            ignoreCase: true
-        });
-        tree.filteringOperands.push(orTree);
-        tree.filteringOperands.push({
-            fieldName: 'CompanyName',
-            condition: IgxStringFilteringOperand.instance().condition('contains'),
-            searchVal: 'd',
-            ignoreCase: true
-        });
-
-        this.grid1.advancedFilteringExpressionsTree = tree;
-    }
-
     public ngOnInit(): void {
         this.displayDensities = [
             { label: 'comfortable', selected: this.density === 'comfortable', togglable: true },
@@ -523,6 +492,36 @@ export class GridFilteringComponent implements OnInit, AfterViewInit {
                 'Contract': false
             }
         ];
+
+        const tree = new FilteringExpressionsTree(FilteringLogic.And);
+        tree.filteringOperands.push({
+            fieldName: 'ID',
+            condition: IgxStringFilteringOperand.instance().condition('contains'),
+            searchVal: 'a',
+            ignoreCase: true
+        });
+        const orTree = new FilteringExpressionsTree(FilteringLogic.Or);
+        orTree.filteringOperands.push({
+            fieldName: 'ID',
+            condition: IgxStringFilteringOperand.instance().condition('contains'),
+            searchVal: 'b',
+            ignoreCase: true
+        });
+        orTree.filteringOperands.push({
+            fieldName: 'CompanyName',
+            condition: IgxStringFilteringOperand.instance().condition('contains'),
+            searchVal: 'c',
+            ignoreCase: true
+        });
+        tree.filteringOperands.push(orTree);
+        tree.filteringOperands.push({
+            fieldName: 'CompanyName',
+            condition: IgxStringFilteringOperand.instance().condition('contains'),
+            searchVal: 'd',
+            ignoreCase: true
+        });
+
+        this.advancedFilteringTree = tree;
     }
 
     public selectDensity(event) {