[stringtemplate-interest] DbNulls in untyped DataRow

[Grzegorz Danowski]

Hi,

 

I have used standard ADO.NET data containers (DataTables, DataRows etc). It
seems that they work well with String Template, but there is one exception
that I've found: problem with DBNull values. Example:

 

        [TestMethod]

        public void DataRowWithEmptyColumn()

        {

            DataTable table = new DataTable();

            table.Columns.Add("CustomerName", typeof(string));

            table.Columns.Add("Birthday", typeof(DateTime));

 

            DataRow newRow = table.NewRow();

            newRow["CustomerName"] = "Bill";

            newRow["Birthday"] = DBNull.Value;

            table.Rows.Add(newRow);

 

            StringTemplate template = new StringTemplate(

                "$data.CustomerName$ " +

                "$data.Birthday; null=\"(unknown)\"$");

 

            template.SetAttribute("data", newRow);

 

            string expected = "Bill (unknown)";

            Assert.AreEqual<string>(expected, template.ToString());

        }

 

Above test fails (actual string is "Bill ").

 

Mean time (writing this post) I have solved my problem: I had used typed
dataset - in this case row has property IsBirthdayNull, my proper template
was:

 

            StringTemplate template = new StringTemplate(

                "$data.CustomerName$ " +

                "$if(!data.BirthdayNull)$$data.Birthday$" +

                "$else$(unknown)$endif$");

 

And it works! I like ST very much!

 

But I wonder if I can use DBNulls with untyped DataRow that has only
IsNull(string columnName) function? 

I have tested an idea:

            StringTemplate template = new StringTemplate(

                "$data.CustomerName$ " +

                "$if(!data.Null(\"Birthday\"))$$data.Birthday$" +

                "$else$(unknown)$endif$"); 

 

Of course test was unsuccessful.

 

Regards,

Gregory

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