TreeListDataColumnFilterRowCellTemplateContext.FilterCriteria Property
Specifies the filter criteria the filter row applies to the data column.
Namespace: DevExpress.Blazor
Assembly: DevExpress.Blazor.v24.1.dll
NuGet Package: DevExpress.Blazor
Declaration
public CriteriaOperator FilterCriteria { get; set; }Property Value
| Type | Description |
|---|---|
| CriteriaOperator | The filter criteria. |
Remarks
When the ShowFilterRow is set to true, the TreeList displays the filter row. The FilterRowCellTemplate property allows you to display a custom editor in the filter row cell. The template’s context parameter contains the FilterCriteria property that specifies the filter criteria applied to the column.
The following code snippet uses the FilterCriteria property to implement a tag box filter for a TreeList column:
@using DevExpress.Data.Filtering
@using DevExpress.Data.Filtering.Helpers
@inject SpaceObjectDataProvider SpaceObjectDataProvider
<DxTreeList @ref="TreeList" Data="TreeListData" ChildrenFieldName="Satellites" ShowFilterRow="true">
<Columns>
<DxTreeListDataColumn FieldName="Name" />
<DxTreeListDataColumn FieldName="TypeOfObject" Caption="Type" Width="30%">
<FilterRowCellTemplate>
<DxTagBox TData="string"
TValue="string"
Data="Types"
Values="GetTagBoxValues(context)"
ValuesChanged="newValues => UpdateCriteria(newValues, context)" />
</FilterRowCellTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="Mass10pow21kg" Caption="Mass, kg" DisplayFormat="N2">
<HeaderCaptionTemplate>Mass, 10<sup>21</sup> × kg</HeaderCaptionTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="MeanRadiusInKM" Caption="Radius, km" DisplayFormat="N2" />
<DxTreeListDataColumn FieldName="Volume10pow9KM3" DisplayFormat="N2">
<HeaderCaptionTemplate>Volume, 10<sup>9</sup> × km<sup>3</sup></HeaderCaptionTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="SurfaceGravity" DisplayFormat="N2">
<HeaderCaptionTemplate>Gravity, m/s<sup>2</sup></HeaderCaptionTemplate>
</DxTreeListDataColumn>
</Columns>
</DxTreeList>
@code {
object TreeListData { get; set; }
IEnumerable<string> Types = new List<string> {
"Star", "Planet", "Satellite", "Dwarf planet", "Asteroid" };
ITreeList TreeList { get; set; }
protected override async Task OnInitializedAsync() {
TreeListData = SpaceObjectDataProvider.GenerateData();
}
IEnumerable<string> GetTagBoxValues(TreeListDataColumnFilterRowCellTemplateContext context) {
if (context.FilterCriteria.ReferenceEqualsNull())
return null;
if (!context.FilterCriteria.Is<InOperator>(out var inOperator))
return null;
if (!inOperator.LeftOperand.Is<OperandProperty>(out var leftOperand))
return null;
if (leftOperand.PropertyName != context.DataColumn.FieldName)
return null;
var result = new List<string>();
foreach (var operand in inOperator.Operands) {
if (!operand.Is<OperandValue>(out var operandValue))
return null;
result.Add((string)operandValue.Value);
}
return result;
}
void UpdateCriteria(IEnumerable<string> newValues,TreeListDataColumnFilterRowCellTemplateContext context){
if (!newValues.Any()) {
context.FilterCriteria = null;
return;
}
context.FilterCriteria = new InOperator(
new OperandProperty(context.DataColumn.FieldName),
newValues.Select(value => new OperandValue(value))
);
}
}
GridDevExtremeDataSource Specifics
The GridDevExtremeDataSource is based on the DevExtreme.AspNet.Data library that uses its own filter language syntax. Some structures of criteria language syntax cannot be converted to DevExtreme data source syntax. This section describes criteria operators that are supported by the GridDevExtremeDataSource.
Binary Operator
The BinaryOperator criteria operator allows you to compare operand property with operand value. You can use the following operator types for comparison: Equal, NotEqual, Greater, GreaterOrEqual, Less, and LessOrEqual.
var criteria = new BinaryOperator("UnitPrice", 20, BinaryOperatorType.Less);
Unary Operator
The UnaryOperator criteria operator allows you to apply Not or IsNull operation to an expression.
var criteria = new UnaryOperator(UnaryOperatorType.Not, new UnaryOperator(UnaryOperatorType.IsNull, "Region"));
Function Operator
The FunctionOperator criteria operator allows you to create a complex filter criteria with the following operator types:
IsNullandIsNullOrEmptyoperands indicate whether a specified operand is a null reference or an empty string.InRangeoperand determines whether a property value is contained in the specified range.StartsWith,EndsWith, andContainsoperands allow you to compare a property with a string value.
var criteria = new FunctionOperator(FunctionOperatorType.StartsWith, new OperandProperty("ShipCountry"), "it");
Group Operator
The GroupOperator criteria operator allows you to create a logical expression that groups two or more operands with a logical AND or OR.
var criteria = new GroupOperator(GroupOperatorType.And,
new BinaryOperator("UnitPrice", 20, BinaryOperatorType.Less),
new FunctionOperator(FunctionOperatorType.StartsWith, new OperandProperty("ShipCountry"), "it"));
Between Operator
The BetweenOperator criteria operator allows you to determine whether a criteria expression lies between the specified range of values.
var criteria = new BetweenOperator("UnitPrice", 15, 20);
In Operator
The InOperator criteria operator allows you to determine whether a property value matches any value in a specified list.
var criteria = new InOperator("ShipCountry", new string[] { "Italy", "German", "France" });