System.Data.Tests.DataSetTest2.Merge_ByDataTable C# (CSharp) Метод

        public void Merge_ByDataTable()
        {
            //create source dataset
            var ds = new DataSet();
            //create datatable
            DataTable dt = DataProvider.CreateParentDataTable();
            dt.TableName = "Table1";
            //add a copy of the datatable to the dataset
            ds.Tables.Add(dt.Copy());

            dt.TableName = "Table2";
            //add primary key
            dt.PrimaryKey = new DataColumn[] { dt.Columns[0] };
            ds.Tables.Add(dt.Copy());
            //now the dataset hase two tables

            //create target dataset (copy of source dataset)
            DataSet dsTarget = ds.Copy();

            dt = ds.Tables["Table2"];
            //update existing row
            dt.Select("ParentId=1")[0][1] = "OldValue1";
            //add new row
            object[] arrAddedRow = new object[] { 99, "NewValue1", "NewValue2", new DateTime(0), 0.5, true };
            dt.Rows.Add(arrAddedRow);
            //delete existing rows
            foreach (DataRow dr in dt.Select("ParentId=2"))
            {
                dr.Delete();
            }

            // Merge - changed values
            dsTarget.Merge(dt);
            Assert.Equal("OldValue1", dsTarget.Tables["Table2"].Select("ParentId=1")[0][1]);

            // Merge - added values
            Assert.Equal(arrAddedRow, dsTarget.Tables["Table2"].Select("ParentId=99")[0].ItemArray);

            // Merge - deleted row
            Assert.Equal(0, dsTarget.Tables["Table2"].Select("ParentId=2").Length);

            //when merging a DataTable with TableName=null, GH throw null reference exception.
            ds = new DataSet();
            dt = new DataTable();
            dt.Columns.Add("Col1");
            dt.Rows.Add(new object[] { 1 });

            // Merge - add a table with no name
            ds.Merge(dt);
            Assert.Equal(1, ds.Tables.Count);

            // Merge - add a table with no name - check Rows.Count
            Assert.Equal(dt.Rows.Count, ds.Tables[0].Rows.Count);
        }