DxGrid.GetColumns() Method

Returns a collection of all grid columns.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v23.1.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. The GetDataColumns() method allows you to get a collection of bound and unbound data columns.

The example below 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()