ExecuteScalar

A tip from Si:
I’m not sure if this has been mentioned before BUT did you know that the ExecuteScalar method on an SqlCommand will cheerfully truncate any string returned through it? That means that XML returned from a stored procedure say may or may not be cut in half depending on its size. The solution is to use the ExecuteXmlReader method instead. Details in this link ExecuteScalar truncates

SQL Output Parameter

I don't why but any SQL Parameters that are defined as outputs are not available until the SqlDataReader has been closed.
So this works:

SqlParameter reservationNumberParameter = new SqlParameter("@ReservationNumber", SqlDbType.NVarChar, 15);
reservationNumberParameter.Direction = ParameterDirection.Output;
command.Parameters.Add(reservationNumberParameter);

reader = command.ExecuteReader();

reader.Close();

reservationNumber = Convert.ToString(reservationNumberParameter.Value);

Whereas this does not work:

SqlParameter reservationNumberParameter = new SqlParameter("@ReservationNumber", SqlDbType.NVarChar, 15);
reservationNumberParameter.Direction = ParameterDirection.Output;
command.Parameters.Add(reservationNumberParameter);

reader = command.ExecuteReader();

reservationNumber = Convert.ToString(reservationNumberParameter.Value);

reader.Close();

DataGridTextColumn Text Alignment

This technique has been superceded by this one DataGridTextColumn Text Alignment

<DataGridTextColumn.CellStyle>
  <Style>
    <Setter Property="FrameworkElement.HorizontalAlignment" Value="Right" />
  </Style>
</DataGridTextColumn.CellStyle>

jQuery Callbacks

A recent foray into jQuery land left me floundering with the callback syntax.

$("#datepicker").datepicker(
  {
    // The CallBack argument is an anonymous function
    onSelect: function(dateText, inst)
    {
      // This invokes the real function
      myCallBackFunction(dateText, inst);
    }
  }
);

// This is the real function that will
// be executed when the onSelect
// invokes its Callback
function myCallBackFunction(dateText,inst)
{
  $("#selectedDate").val(dateText);
}

With a simple callback function the anonymous function can contain the processing.

$("#datepicker").datepicker(
  {
    // The CallBack argument is an anonymous function
    onSelect: function(dateText, inst)
    {
      $("#selectedDate").val(dateText);
    }
  }
);

ResourceStrings Access Modifier

When a new Resource file is added to a project the Access Modifier defaults to Internal.

There is a small combobox at the top of the Resource editor that allows it to be changed.

COM Data Types

Data type conversions from COM to .Net

IDL Type	.NET Type
char	System.SByte
short	System.Int16
int, long, HRESULT and SCODE	System.Int32
int64	System.Int64
unsigned char	System.Byte
unsigned short	System.UInt16
unsigned int and unsigned long	System.UInt32
uint64	System.UInt64
float	System.Single
double	System.Double
BSTR, LPSTR and LPWSTR	System.String
VARIANT_BOOL	System.Boolean
DATE	System.DateTime
GUID	System.Guid
DECIMAL	System.Decimal
CURRENCY	System.Decimal
VARIANT	System.Object
IUnknown*	System.Object
IDispatch*	System.Object
void*	System.IntPtr
IDispatchEx*	System.Runtime.InteropServices.Expando.IExpando
IEnumVariant*	System.Collections.IEnumerator

COM	IDL
boolean and small	char
wchar_t	unsigned short
hyper and __int64	int64
[string] char*	LPSTR
[string] wchar_t*	LPWSTR
byte	unsigned char
unsigned hyper and unsigned __int64	uint64

MouseOver Triggers

Here is a minimal example of changing the background colour of a TextBlock when MouseOver is detected.

<Window.Resources>
    <Style TargetType="TextBlock">
        <Style.Triggers>
            <Trigger Property="IsMouseOver" Value="True">
                <Setter Property="Background" Value="Pink" />
            </Trigger>
        </Style.Triggers>
    </Style>
</Window.Resources>
<StackPanel>
    <TextBlock>Hello World</TextBlock>
</StackPanel>