public void ConstantFoldingDoesPreserveType()
{
DataTable dataTable = new DataTable();
dataTable.Columns.Add("NonNullInt", typeof(int));
dataTable.Columns.Add("NullInt", typeof(int));
DataRow dataRow = dataTable.NewRow();
dataRow["NonNullInt"] = 1;
dataTable.Rows.Add(dataRow);
DataColumnPropertyBinding[] dataRowProperties = DataRowPropertyProvider.GetProperties(dataTable);
DataContext dataContext = new DataContext();
dataContext.Constants.Add("DataRow", dataRow, dataRowProperties);
Expression <object> exprWithNonNullInt = new Expression <object>();
exprWithNonNullInt.DataContext = dataContext;
exprWithNonNullInt.Text = "DataRow.NonNullInt";
Assert.AreEqual(typeof(int), exprWithNonNullInt.Resolve());
Assert.AreEqual(1, exprWithNonNullInt.Evaluate());
Expression <object> exprWithNullInt = new Expression <object>();
exprWithNullInt.DataContext = dataContext;
exprWithNullInt.Text = "DataRow.NullInt";
Assert.AreEqual(typeof(int), exprWithNullInt.Resolve());
Assert.AreEqual(null, exprWithNullInt.Evaluate());
}
public void DBNullAsPropertyValue()
{
DataTable dataTable = new DataTable();
dataTable.Columns.Add("ID1", typeof(int));
dataTable.Columns.Add("ID2", typeof(int));
DataRow dataRow = dataTable.Rows.Add(DBNull.Value, DBNull.Value);
Expression <bool> expression = new Expression <bool>();
expression.Text = "row.ID1 = row.ID2";
expression.Parameters.Add("row", typeof(DataRow), dataRow, DataRowPropertyProvider.GetProperties(dataTable));
Assert.IsFalse(expression.Evaluate());
}
public void DataRowProperties()
{
Query query = QueryFactory.CreateQuery();
query.Text = @"
SELECT e.EmployeeID,
e.FirstName,
e.LastName
FROM Employees e
WHERE e.EmployeeID BETWEEN 1 AND 2
ORDER BY 1
";
DataTable result = query.ExecuteDataTable();
Assert.AreEqual(2, result.Rows.Count);
Expression <object> expr = new Expression <object>();
expr.DataContext = query.DataContext;
ParameterBinding param = new ParameterBinding("@ROW", typeof(DataRow), DataRowPropertyProvider.GetProperties(result));
expr.Parameters.Add(param);
param.Value = result.Rows[0];
expr.Text = "@ROW.EmployeeID";
Assert.AreEqual(1, expr.Evaluate());
expr.Text = "@ROW.FirstName";
Assert.AreEqual("Nancy", expr.Evaluate());
expr.Text = "@ROW.LastName";
Assert.AreEqual("Davolio", expr.Evaluate());
param.Value = result.Rows[1];
expr.Text = "@ROW.EmployeeID";
Assert.AreEqual(2, expr.Evaluate());
expr.Text = "@ROW.FirstName";
Assert.AreEqual("Andrew", expr.Evaluate());
expr.Text = "@ROW.LastName";
Assert.AreEqual("Fuller", expr.Evaluate());
}
