DxGrid.GetColumns() Method

Returns a collection of all grid columns.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v24.1.dll

NuGet Package: DevExpress.Blazor

Declaration

public IReadOnlyList<IGridColumn> GetColumns()

Returns

Type	Description
IReadOnlyList<IGridColumn>	The column collection.

Remarks

Call the Grid’s GetVisibleColumns() method to get a collection of visible columns sorted based on their display order. To get a collection of all grid columns, call the GetColumns method. Whenever these methods encounter a band, they include it followed by all its nested columns in the collection. If nested bands exist, the methods add them and their nested columns recursively.

The GetDataColumns() method allows you to get a collection of bound and unbound data columns.

The following code snippet shows the difference between the results of the GetColumns and GetVisibleColumns methods.

Razor

@using Grid.Data
@inject WeatherForecastService ForecastService

<DxGrid Data="@Data" @ref="@MyGrid"
        ShowFilterRow="true"
        @bind-SelectedDataItems="@SelectedDataItems">
    <Columns>
        <DxGridSelectionColumn VisibleIndex="1"/>
        <DxGridCommandColumn NewButtonVisible="false" EditButtonVisible="false"
                             DeleteButtonVisible="false" VisibleIndex="0" />
        <DxGridDataColumn FieldName="TemperatureC" VisibleIndex="3" />
        <DxGridDataColumn FieldName="TemperatureF" VisibleIndex="4" />
        <DxGridDataColumn FieldName="Date" DisplayFormat="D" VisibleIndex="2" />
        <DxGridDataColumn FieldName="Forecast" />
        <DxGridDataColumn FieldName="CloudCover" />
    </Columns>
</DxGrid>

<DxButton Click="@OnGetColumns">Get Columns</DxButton>
<DxButton Click="@OnGetVisibleColumns">Get Visible Columns</DxButton>

<p/>
<div><b>Columns</b>: @ColumnInfo</div>
<div><b>Visible Columns</b>: @VisibleColumnInfo</div>

@code {
    IGrid MyGrid { get; set; }
    object Data { get; set; }
    string ColumnInfo { get; set; }
    string VisibleColumnInfo { get; set; }
    IReadOnlyList<object> SelectedDataItems { get; set; }

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

    void OnGetColumns() {
        ColumnInfo = GetColumnInfo(MyGrid.GetColumns());
    }

    void OnGetVisibleColumns() {
        VisibleColumnInfo = GetColumnInfo(MyGrid.GetVisibleColumns());
    }

    string GetColumnInfo(IEnumerable<IGridColumn> columns) {
        var columnInfo = columns.Select((column, index) => (1 + index) + " - " + column switch
        {
            IGridDataColumn dataColumn => dataColumn.FieldName,
            IGridSelectionColumn => "Selection Column",
            IGridCommandColumn => "Command Column",
            _ => null
        });
        return string.Join("; ", columnInfo);
    }
}

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>();

Implements

GetColumns()