GridHeaderCommandContext.Column Property

Returns a column that contains the target cell.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v25.2.dll

Declaration

public IGridColumn Column { get; }

Property Value

Type	Description
IGridColumn	A Grid column.

Remarks

The DevExpress Blazor Grid allows you to display context menus with predefined and custom commands. Use the ContextMenus property to activate context menus for specific Grid elements. Handle the CustomizeContextMenu event to modify the menu item collection. Use the Context event argument to identify the target Grid element and obtain contextual information.

When the target element is a header cell, the Context property returns a GridHeaderCommandContext object. Use the object’s Column property to access a column containing the target cell.

Example

The following code snippet customizes commands available in the header context menu:

Razor

@inject WeatherForecastService ForecastService

<DxGrid Data="@Data" ContextMenus="GridContextMenus.Header" CustomizeContextMenu="CustomizeContextMenu">
    <Columns>
        <DxGridSelectionColumn />
        <DxGridDataColumn FieldName="Date" DisplayFormat="D" />
        <DxGridDataColumn FieldName="TemperatureC" Caption="@("Temp. (\x2103)")" Width="120px" />
        <DxGridDataColumn FieldName="TemperatureF" Caption="@("Temp. (\x2109)")" Width="120px" />
        <DxGridDataColumn FieldName="Forecast" />
        <DxGridDataColumn FieldName="CloudCover" />
    </Columns>
</DxGrid>

@code {
    object Data { get; set; }

    protected override void OnInitialized() {
        Data = ForecastService.GetForecast();
    }

    void CustomizeContextMenu(GridCustomizeContextMenuEventArgs args) {
        if (args.Context is GridHeaderCommandContext headerContext) {
            // Customizes context menu commands for the Date column header
            if (headerContext.Column is IGridDataColumn dataColumn && dataColumn.FieldName == "Date") {
                args.Items.Remove(GridContextMenuDefaultItemNames.GroupByColumn);
                args.Items.Remove(GridContextMenuDefaultItemNames.UngroupColumn);
            }
            // Customizes context menu commands for the selection column header
            if (headerContext.Column is IGridSelectionColumn selectionColumn) {
                var isFixed = selectionColumn.FixedPosition != GridColumnFixedPosition.None;
                string itemText = isFixed ? "Unfix Column" : "Fix Column to the Left";
                var newValue = isFixed ? GridColumnFixedPosition.None : GridColumnFixedPosition.Left;

                args.Items.AddCustomItem(itemText, () => {
                    headerContext.Grid.BeginUpdate();
                    headerContext.Column.FixedPosition = newValue;
                    headerContext.Grid.EndUpdate();
                });
            }
        }
    }
}

WeatherForecast

using System;

public class WeatherForecast {
    public DateTime Date { get; set; }
    public int TemperatureC { get; set; }
    public double TemperatureF => Math.Round((TemperatureC * 1.8 + 32), 2);
    public string Forecast { get; set; }
    public string CloudCover { get; set; }
    public bool Precipitation { get; set; }
}

WeatherForecastService

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

public class WeatherForecastService {
    private List<WeatherForecast> Forecast { get; set; }

    private static string[] CloudCover = new[] {
        "Sunny", "Partly cloudy", "Cloudy", "Storm"
    };

    Tuple<int, string>[] ConditionsForForecast = new Tuple<int, string>[] {
        Tuple.Create( 22 , "Hot"),
        Tuple.Create( 13 , "Warm"),
        Tuple.Create( 0 , "Cold"),
        Tuple.Create( -10 , "Freezing")
    };

    public WeatherForecastService() {
        Forecast = CreateForecast();
    }

    private List<WeatherForecast> CreateForecast() {
        var rng = new Random();
        DateTime startDate = DateTime.Now;
        return Enumerable.Range(1, 15).Select(index => {
            var temperatureC = rng.Next(-10, 30);
            return new WeatherForecast {
                Date = startDate.AddDays(index),               
                TemperatureC = temperatureC,
                CloudCover = CloudCover[rng.Next(0, 4)],
                Precipitation = Convert.ToBoolean(rng.Next(0, 2)),
                Forecast = ConditionsForForecast.First(c => c.Item1 <= temperatureC).Item2
            };
        }).ToList();
    }

    public IEnumerable<WeatherForecast> GetForecast() {
        return Forecast.ToArray();
    }
    // ...
}

Program.cs

// ...
builder.Services.AddSingleton<WeatherForecastService>();