Grid Filter Row
One of the filter modes of the grid is a row of filter elements below the column headers.
In this article:
Basics
To enable the filter row set the FilterMode property of the grid to Telerik.Blazor.GridFilterMode.FilterRow.
The grid will render a row below the column headers with UI that you can use to fill in the filter criteria. You can type in the input to execute the default operator as you type, or click a button to choose a different filter operator (like "contains", "greater than" and so on). Filters are applied as the user types in the inputs. Once you enter a filter criteria, the clear button will be enabled to allow you to reset the filter state.
Filter Row in Telerik Grid
@* Filter row mode *@
<TelerikGrid Data=@GridData FilterMode="Telerik.Blazor.GridFilterMode.FilterRow" Pageable="true" Height="400px">
<GridColumns>
<GridColumn Field=@nameof(Employee.Name) />
<GridColumn Field=@nameof(Employee.AgeInYears) Title="Age" />
<GridColumn Field=@nameof(Employee.HireDate) Title="Hire Date" />
<GridColumn Field=@nameof(Employee.IsOnLeave) Title="On Vacation" />
</GridColumns>
</TelerikGrid>
@code {
public List<Employee> GridData { get; set; }
protected override void OnInitialized()
{
GridData = new List<Employee>();
var rand = new Random();
for (int i = 0; i < 100; i++)
{
GridData.Add(new Employee()
{
EmployeeId = i,
Name = "Employee " + i.ToString(),
AgeInYears = rand.Next(10, 80),
HireDate = DateTime.Now.Date.AddDays(rand.Next(-20, 20)),
IsOnLeave = i % 3 == 0
});
}
}
public class Employee
{
public int? EmployeeId { get; set; }
public string Name { get; set; }
public int? AgeInYears { get; set; }
public DateTime HireDate { get; set; }
public bool IsOnLeave { get; set; }
}
}
Filter From Code
You can set the grid filters from your code through the grid state.
If you want to set an initial state to the Grid, use a similar snippet, but in the
OnStateInit event
Set filtering programmatically
@* This snippet shows how to set filtering state to the grid from your code
Applies to the FilterRow mode *@
@using Telerik.DataSource;
<TelerikButton ThemeColor="primary" OnClick="@SetGridFilter">Filter From Code</TelerikButton>
<TelerikGrid @ref="@GridRef"
Data="@GridData"
Height="400px"
Pageable="true"
FilterMode="@GridFilterMode.FilterRow">
<GridColumns>
<GridColumn Field="@(nameof(SampleData.Id))" Width="150px" />
<GridColumn Field="@(nameof(SampleData.Name))" Title="Employee Name" />
<GridColumn Field="@(nameof(SampleData.Team))" Title="Team" />
<GridColumn Field="@(nameof(SampleData.HireDate))" Title="Hire Date" />
</GridColumns>
</TelerikGrid>
@code {
private TelerikGrid<SampleData> GridRef { get; set; }
private async Task SetGridFilter()
{
GridState<SampleData> desiredState = new GridState<SampleData>()
{
FilterDescriptors = new List<IFilterDescriptor>()
{
new CompositeFilterDescriptor(){
FilterDescriptors = new FilterDescriptorCollection()
{
new FilterDescriptor() { Member = "Id", Operator = FilterOperator.IsGreaterThan, Value = 10, MemberType = typeof(int)}
}
},
new CompositeFilterDescriptor()
{
FilterDescriptors = new FilterDescriptorCollection()
{
new FilterDescriptor() { Member = "Team", Operator = FilterOperator.Contains, Value = "3", MemberType = typeof(string) },
}
}
}
};
await GridRef.SetStateAsync(desiredState);
}
private IEnumerable<SampleData> GridData = Enumerable.Range(1, 30).Select(x => new SampleData
{
Id = x,
Name = "name " + x,
Team = "team " + x % 5,
HireDate = DateTime.Now.AddDays(-x).Date
});
public class SampleData
{
public int Id { get; set; }
public string Name { get; set; }
public string Team { get; set; }
public DateTime HireDate { get; set; }
}
}
Customization
The Grid allows you to customize the default behavior of the Filter Row in a couple ways:
Debouncing the Filtering
By default, the filtering will be debounced with 150ms. Configure that with the following component parameter:
| Parameter | Type and Default Value | Description |
|---|---|---|
FilterRowDebounceDelay |
int 150 |
Time in milliseconds between the last typed symbol in the input and the actual filtering. Affects how fast the component initiates filtering. Use it to balance between client-side performance and number of database queries. |
Configuring the Filter Row
You can override the default Filter Row behavior for each column through the following properties the GridColumn exposes:
| Parameter | Type and Default Value | Description |
|---|---|---|
DefaultFilterOperator |
FilterOperator |
Sets the default filter operator in the column it is declared for. Accepts a member of the FilterOperator enum. The selected operator must be applicable for the specific data type. Check the supported options in the Filter Operators article. |
FilterOperators |
List<FilterListOperator> |
Specifies the available operators. Must contain only supported filter operators for the specific data type. If not defined, the component will use a default list of available operators based on the field type. |
ShowFilterCellButtons |
bool ( true) |
controls the visibility of the filter buttons |
Configure the Filter Row
@*Customize the Filter Row*@
@using Telerik.DataSource
<TelerikGrid Data="@MyData"
Height="400px"
Pageable="true"
FilterMode="@GridFilterMode.FilterRow"
FilterRowDebounceDelay="200">
<GridColumns>
<GridColumn DefaultFilterOperator="FilterOperator.IsEqualTo"
ShowFilterCellButtons="false"
Field="@(nameof(SampleData.Id))" Width="120px" />
<GridColumn DefaultFilterOperator="FilterOperator.StartsWith"
ShowFilterCellButtons="false"
Field="@(nameof(SampleData.Name))" Title="Employee Name" />
<GridColumn DefaultFilterOperator="FilterOperator.Contains"
ShowFilterCellButtons="false" Field="@(nameof(SampleData.Team))" Title="Team" />
<GridColumn DefaultFilterOperator="FilterOperator.IsGreaterThanOrEqualTo"
ShowFilterCellButtons="false" Field="@(nameof(SampleData.HireDate))" Title="Hire Date" />
</GridColumns>
</TelerikGrid>
@code {
public IEnumerable<SampleData> MyData = Enumerable.Range(1, 30).Select(x => new SampleData
{
Id = x,
Name = "name " + x,
Team = "team " + x % 5,
HireDate = DateTime.Now.AddDays(-x).Date
});
public class SampleData
{
public int Id { get; set; }
public string Name { get; set; }
public string Team { get; set; }
public DateTime HireDate { get; set; }
}
}
Filter Row Template
The template will let you have full control over the Filter Row rendering and behavior. See how you can implement it and explore the example in the Filter Row Template article.