Dataset updating

I've created a github repo https://github.com/sceneskope/powerbi that has an example of the problem.

The Samples/Streaming Sample project runs correctly and writes data every 5 seconds with no errors.

dataset updating-27

I can see the dataset and all the counters, but the data is empty. But now when I'm trying to refresh the data, even though the columns Orange and Purple were empty, I'm getting an error that says"Expression.The only way I know how to update my dataset in Power BI is to delete it and add it again, which deletes associated reports and dashboards.If I simply add a new column to my data model, is that what i really have to do to see the changes?This document describes how to create, update, and manage datasets in Big Query. Datasets enable you to organize and control access to your tables and views.

A table or view must belong to a dataset, so you need to create at least one dataset before loading data into Big Query.

The program that follows uses the weekly information to update the year-to-date data set and displays the new data set.

The RENAME= data set option in the UPDATE statement changes the name of the variable Sales in the transaction data set (WEEK_SALES) to New Sales.

In this example, a bookstore uses SAS to keep track of weekly sales and year-to-date sales.

The program that follows creates, sorts by Title, and displays the data set, YEAR_SALES, which contains the year-to-date information.

I am using one of the control as an example to understand this , its a rad Text Box(txt Email) whose databinding Text property is set to Patient Binding Source - email , Data Source Update mode is On Property Changed i add this code to update dataset , this only update first character or give me some error Private Sub txt Email_Text Changed(By Val sender As Object, By Val e As System.