Components / Grid / Export

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CSV Export

You can export the grid to CSV with a click of a button. The current filter, sort, page, grouping and column order are applied to the .csv document.

When you click the Export button, your browser will receive the resulting file.

In This Article

Basics

To enable the grid CSV Export, add a command button with the CsvExport command name to the Grid toolbar.

<GridToolBarTemplate>
    <GridCommandButton Command="CsvExport" Icon="@SvgIcon.FileCsv">Export to CSV</GridCommandButton>
</GridToolBarTemplate>

Optionally, you can also set the GridCsvExport tag settings under the GridExport tag to choose:

  • FileName - the name of the file. The grid will add the .csv extension for you.
  • AllPages - whether to export the current page only, or the entire data from the data source.
  • Subscribe to Grid export events that allow further customizations of the exported columns or data.

Export the Grid to CSV - Example

@* You can sort, group, filter, page the grid, reorder its columns, and you can click the
    Export button to save the current data *@

<TelerikGrid Data="@GridData" Pageable="true" Sortable="true" Reorderable="true"
             FilterMode="@GridFilterMode.FilterRow" Groupable="true">

    <GridToolBarTemplate>
        <GridCommandButton Command="CsvExport" Icon="@SvgIcon.FileCsv">Export to CSV</GridCommandButton>
        <label class="k-checkbox-label"><TelerikCheckBox @bind-Value="@ExportAllPages" />Export All Pages</label>
    </GridToolBarTemplate>

    <GridExport>
        <GridCsvExport FileName="telerik-grid-export" AllPages="@ExportAllPages" />
    </GridExport>

    <GridColumns>
        <GridColumn Field="@nameof(SampleData.ProductId)" Title="ID" />
        <GridColumn Field="@nameof(SampleData.ProductName)" Title="Product Name" />
        <GridColumn Field="@nameof(SampleData.UnitsInStock)" Title="In stock" />
        <GridColumn Field="@nameof(SampleData.Price)" Title="Unit Price" />
        <GridColumn Field="@nameof(SampleData.Discontinued)" Title="Discontinued" />
        <GridColumn Field="@nameof(SampleData.FirstReleaseDate)" Title="Release Date" />
    </GridColumns>
</TelerikGrid>

@code {
    List<SampleData> GridData { get; set; }
    bool ExportAllPages { get; set; }

    protected override void OnInitialized()
    {
        GridData = Enumerable.Range(1, 100).Select(x => new SampleData
        {
            ProductId = x,
            ProductName = $"Product {x}",
            UnitsInStock = x * 2,
            Price = 3.14159m * x,
            Discontinued = x % 4 == 0,
            FirstReleaseDate = DateTime.Now.AddDays(-x)
        }).ToList();
    }

    public class SampleData
    {
        public int ProductId { get; set; }
        public string ProductName { get; set; }
        public int UnitsInStock { get; set; }
        public decimal Price { get; set; }
        public bool Discontinued { get; set; }
        public DateTime FirstReleaseDate { get; set; }
    }
}

Programmatic Export

You can programmatically invoke the export feature of the Grid, by using the following methods exposed on the @ref of the Grid:

  • SaveAsCsvFileAsync - ValueTask - sends the exported CSV file to the browser for download
  • ExportToCsvAsync - Task<MemoryStream> - returns the exported data as a MemoryStream. The stream itself is finalized, so that the resource does not leak. To read and work with the stream, clone its available binary data to a new MemoryStream instance.

The same methods are exposed for exporting an Excel file.

Invoke the export function from code

@* Send the exported file for download and get the exported data as a memory stream *@

@using System.IO

<TelerikButton OnClick="@(async () => await GridRef.SaveAsCsvFileAsync())">Download the CSV file</TelerikButton>
<TelerikButton OnClick="@GetTheDataAsAStream">Get the Exported Data as a MemoryStream</TelerikButton>

<TelerikGrid @ref="@GridRef"
             Data="@GridData"
             Pageable="true"
             Sortable="true"
             Reorderable="true"
             FilterMode="@GridFilterMode.FilterRow"
             Groupable="true">

    <GridToolBarTemplate>
        <GridCommandButton Command="CsvExport" Icon="@SvgIcon.FileCsv">Export to CSV</GridCommandButton>
        <label class="k-checkbox-label"><TelerikCheckBox @bind-Value="@ExportAllPages" />Export All Pages</label>
    </GridToolBarTemplate>

    <GridExport>
        <GridCsvExport FileName="telerik-grid-export" AllPages="@ExportAllPages" />
    </GridExport>

    <GridColumns>
        <GridColumn Field="@nameof(SampleData.ProductId)" Title="ID" />
        <GridColumn Field="@nameof(SampleData.ProductName)" Title="Product Name" />
        <GridColumn Field="@nameof(SampleData.UnitsInStock)" Title="In stock" />
        <GridColumn Field="@nameof(SampleData.Price)" Title="Unit Price" />
        <GridColumn Field="@nameof(SampleData.Discontinued)" Title="Discontinued" />
        <GridColumn Field="@nameof(SampleData.FirstReleaseDate)" Title="Release Date" />
    </GridColumns>
</TelerikGrid>

@code {
    private TelerikGrid<SampleData> GridRef { get; set; }

    private MemoryStream exportedCSVStream { get; set; }

    private async Task GetTheDataAsAStream()
    {
        MemoryStream finalizedStream = await GridRef.ExportToCsvAsync();

        exportedCSVStream = new MemoryStream(finalizedStream.ToArray());
    }

    List<SampleData> GridData { get; set; }
    bool ExportAllPages { get; set; }

    protected override void OnInitialized()
    {
        GridData = Enumerable.Range(1, 100).Select(x => new SampleData
            {
                ProductId = x,
                ProductName = $"Product {x}",
                UnitsInStock = x * 2,
                Price = 3.14159m * x,
                Discontinued = x % 4 == 0,
                FirstReleaseDate = DateTime.Now.AddDays(-x)
            }).ToList();
    }

    public class SampleData
    {
        public int ProductId { get; set; }
        public string ProductName { get; set; }
        public int UnitsInStock { get; set; }
        public decimal Price { get; set; }
        public bool Discontinued { get; set; }
        public DateTime FirstReleaseDate { get; set; }
    }
}

Customization

To customize the exported file, handle the OnBeforeExport or OnAfterExport events the Grid exposes.

The component allows you to control the data set that will be exported. It also provides built-in customization options for the columns, such as Width, Title, and more.

For more advanced customizations (such as coloring the headers, bolding the titles, or even changing cell values) the Grid lets you get the MemoryStream of the file. Thus, you can customize it using the SpreadProcessing or the SpreadStreamProcessing libraries that are available with your license.

Read more about how to customize the exported file...

Notes

The CSV export has the following specifics:

  • Column widths are not applied because a CSV document does not have such a concept. You can use any units in the grid itself, they will not be reflected in the exported document. If you need to add such structure, consider exporting to an Excel file.

  • Templates are not exported, because there is no provision in the framework for getting them at runtime. If a column, header or group header/footer has a template or aggregates, it will be ignored. The headers will be the Title of the column, the data is the data from the Field. If you need additional information, see if you can add it in a Field in the model, or create your own Excel file. Find a project example on how to generate your own exported file.

  • bool fields are exported as TRUE or FALSE strings, because there is no boolean data type in Excel and these string values are the most common ones used in data and macros.

  • Date and number formats are exported with the following format: mm/dd/yyyy hh:mm:ss plus the current app culture AM/PM specifier for dates, and Convert.ToDouble(value) for numbers (which uses the current thread culture). The Excel date formats are different than .NET date formats and Excel may not always recognize the column as dates, for example, if the entire date format from the .NET culture is used.

  • The Grid exports only <GridColumn> instances. Other types of columns are not exported, for example command, checkbox, hierarchy, group and row-drag columns.

  • If the Grid is using OnRead and is exporting all pages, it will fire an additional OnRead event at the time of exporting, with a request PageSize of 0. This will enable the component to obtain all data.

  • With Server-side Blazor, the file may become larger than the default SignalR connection limit, and this can disconnect the client and result in an error. Generally, this requires quite a lot of data to happen, but you may need to increase the size limit of the connection in the ConfigureServices method of your Startup.cs file, for example:

    C#

        services.AddServerSideBlazor().AddHubOptions(o =>
    {
        o.MaximumReceiveMessageSize = 1024 * 1024; // 1MB
    });

  • With Client-side Blazor (WebAssembly), all the code runs in the browser and, at the time of writing, is considerably slower than server-side Blazor, and it only has one actual thread. This means that while the file is being generated, the UI will be unresponsive, so you may want to show a loading sign to the user through the OnClick handler of the command button, something like:

    Component

    @* Exporting a lot of rows can be slow in a WebAssembly app more so than in a server-side app, and it blocks the UI *@

<TelerikGrid Data="@GridData" AutoGenerateColumns="true" Pageable="true">
    <GridToolBarTemplate>
        <GridCommandButton OnClick="@ShowLoadingSign" Command="ExcelExport" Icon="@SvgIcon.FileExcel">Export to Excel</GridCommandButton>
        <GridCommandButton OnClick="@ShowLoadingSign" Command="CsvExport" Icon="@SvgIcon.FileCsv">Export to CSV</GridCommandButton>
    </GridToolBarTemplate>
    <GridExport>
        <GridExcelExport AllPages="true" FileName="telerik-grid-export" />
        <GridCsvExport AllPages="true" FileName="telerik-grid-export" />
    </GridExport>
</TelerikGrid>

<TelerikWindow Visible="@isExporting" Modal="true">
    <WindowTitle>Please wait...</WindowTitle>
    <WindowContent>We are exporting your data, your file will download shortly.</WindowContent>
</TelerikWindow>

@code {
    bool isExporting { get; set; }

    async Task ShowLoadingSign()
    {
        isExporting = true;
        StateHasChanged();
        // This won't work for server-side Blazor, the UI will render immediately after the delay and the loading sign will only flicker
        await Task.Delay(50);
        isExporting = false;
    }

    List<SampleData> GridData { get; set; }

    protected override void OnInitialized()
    {
        GridData = Enumerable.Range(1, 1000).Select(x => new SampleData
        {
            ProductId = x,
            ProductName = $"Product {x}",
            UnitsInStock = x * 2,
            Price = 3.14159m * x,
            Discontinued = x % 4 == 0,
            FirstReleaseDate = DateTime.Now.AddDays(-x)
        }).ToList();
    }

    public class SampleData
    {
        public int ProductId { get; set; }
        public string ProductName { get; set; }
        public int UnitsInStock { get; set; }
        public decimal Price { get; set; }
        public bool Discontinued { get; set; }
        public DateTime FirstReleaseDate { get; set; }
    }
}

See Also

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