I have used some time now on integrating with monday. And a lot of people here has been very helpful so want to give a little back. This is just POC code but can properly help some getting started with c#. I will start to extend it for production and return in some weeks with more functionality.

How to use the code

var boardId = "111";

var groupId = "topics";



var monday = new Monday(_config.MondayAPIKey);



var columnValues = new List<IMondayColumn>();



var systemObservationColumn = new LongTextColumn("long_text", "LongTextColumn text");

columnValues.Add(systemObservationColumn);



var actionColumn = new LongTextColumn("long_text1", "LongTextColumn text");

columnValues.Add(actionColumn);



var warningGivenToColumn = new PersonColumn("person", "13958870");

columnValues.Add(warningGivenToColumn);



var typeColumn = new DropDownColumn("dropdown", "Due date");

columnValues.Add(typeColumn);



var result = await monday.InsertItem(boardId, groupId, "Tester 2", columnValues);

The code:

public interface IMondayColumn

{

    string GetJSON();

}



public class DropDownColumn : IMondayColumn

{

    string _label;

    string _columnName;



    public DropDownColumn(string columnName, string label)

    {

        _columnName = columnName;

        _label = label;

    }

    public string GetJSON()

    {

        return @"\\\\\\"""+_columnName+@"\\\\\\"":{\\\\\\""labels\\\\\\"":[\\\\\\"""+_label+@"\\\\\\""]}";

    }

}



public class LongTextColumn : IMondayColumn

{

    string _text;

    string _columnName;

    public LongTextColumn(string columnName, string text)

    {

        _columnName = columnName;

        _text = text;

    }

    public string GetJSON()

    {

        return @"\\\\\\"""+_columnName+@"\\\\\\"": { \\\\\\""text\\\\\\"": \\\\\\""" + _text+ @"\\\\\\""}";

    }

}



public class PersonColumn : IMondayColumn

{

    string _userId;

    string _columnName;



    public PersonColumn(string columName, string userId)

    {

        _userId = userId;

        _columnName = columName;

    }



    public string GetJSON()

    {

        return @"\\\\\\"""+_columnName+@"\\\\\\"":{\\\\\\""personsAndTeams\\\\\\"":[{\\\\\\""id\\\\\\"":"+_userId+@",\\\\\\""kind\\\\\\"":\\\\\\""person\\\\\\""}]}";

    }

}



public class Monday

{

	string _apiKey;

	string MondayApiUrl = "https://api.monday.com/v2/";



	public Monday(string apiKey)

    {

		_apiKey = apiKey;

	}



	public async Task<string> InsertItem(string boardId, string groupId, string itemName, List<IMondayColumn> columnValues)

    {

		var columnValuesStr = GetColumnValuesFronList(columnValues);

		//var query = @"{""query"": ""mutation {create_item(board_id: 674077648, group_id:\\""topics\\"", item_name: \\""adding works\\"", column_values: \\"" {\\\\\\""long_text\\\\\\"": { \\\\\\""text\\\\\\"": \\\\\\""Sample text\\\\\\""}} \\"") {id}  }"" }";

		var query = @"{""query"": ""mutation {create_item(board_id: "+boardId+@", group_id:\\"""+groupId+@"\\"", item_name: \\"""+itemName+@"\\"", column_values: \\"" {" + columnValuesStr + @"} \\"") {id}  }"" }";









		return await Query(query);

    }



	string GetColumnValuesFronList(List<IMondayColumn> columnValues)

    {

		string columnValuesStr = string.Empty;



		foreach(var column in columnValues)

        {

			columnValuesStr += column.GetJSON()+",";

		}

		columnValuesStr = columnValuesStr.Trim(',');



		return columnValuesStr;



	}



	public async Task<string> Query(string query)

	{

		byte[] dataBytes = System.Text.Encoding.UTF8.GetBytes(query);



		HttpWebRequest request = (HttpWebRequest)WebRequest.Create(MondayApiUrl);

		request.ContentType = "application/json";

		request.Method = "POST";

		request.Headers.Add("Authorization", _apiKey);



		using (Stream requestBody = request.GetRequestStream())

		{

			await requestBody.WriteAsync(dataBytes, 0, dataBytes.Length);

		}



		using (HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())

		using (Stream stream = response.GetResponseStream())

		using (StreamReader reader = new StreamReader(stream))

		{

			return await reader.ReadToEndAsync();

		}

	}

}