Dynamically create the dataset using a key-value pair list by using the Expando

Posted by: damian.haynes on 2 December 2020, 8:46 am EST

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    Posted 2 December 2020, 8:46 am EST

    Hey there,

    Using the template function in .net Core 3.1 code.

    We created a class with a Date Field and a List of string values. This DataSet merged successfully.

    We then tried to dynamically create the same using a key-value pair list by using the Expando class. But this failed, so we trimmed it back to just one item the Date Field.

    A1 B1

    FileDate {{ds.FileDate}}

    Using the immediate window in VS we can see the FileDate


    {1/01/2020 3:21:00 PM}

    Date: {1/01/2020 12:00:00 AM}

    Day: 1

    DayOfWeek: Wednesday

    DayOfYear: 1

    Hour: 15

    Kind: Unspecified

    Millisecond: 0

    Minute: 21

    Month: 1

    Second: 0

    Ticks: 637134888600000000

    TimeOfDay: {15:21:00}

    Year: 2020

    The exception raised is

    System.ArgumentException: 'Can’t find field or property ‘FileDate’ of type 'System.Collections.Generic.KeyValuePair`2

    The test method is


    public void Generate_SampleData_SavesExcelFile()


    var templateFileLocation = @“C:\samplefiles\input.xltx”;

    var outboundFileLocation = @“C:\samplefiles\gen”;

    // Create a Key/Value pair for all fields and the Grid

    dynamic expando = new ExpandoObject();

    IDictionary<string, object> expandoDic = (IDictionary<string, object>)expando;

    // Fields

    expandoDic.Add(“FileDate”, new DateTime(2020, 1, 1, 15, 21, 00));

    // Excel

    Workbook workbook = new Workbook();


    //Add data source

    workbook.AddDataSource(“ds”, expando);

    //Invoke to process the template




    Is there something wrong in the above code, or this method is not supported?



  • Posted 3 December 2020, 10:27 pm EST

    Hi Damian,

    Sorry, but we do not face any kind of error at our end. Please see the attached sample and let us know if you are doing anything else.

    Also, the object that you are assigning to the data source is not supported. Please see the documentation below to see how you can data bind the excel:


    If you have any other issues then please let us know.


    Prabhat Sharma.

  • Posted 3 December 2020, 10:27 pm EST

  • Posted 12 April 2023, 8:14 pm EST

    Hi Prabhat,

    Can you please attach template for above given code? I am trying to test same but excel is coming empty.

  • Posted 13 April 2023, 6:33 pm EST

    Hello Anil,

    Your query has been replied to your support case CAS-39634-Z6K7M2.

    Please continue the thread there only to avoid confusion.


    Prabhat Sharma.

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