MATLAB COM Builder

Data Conversion Flags

Data conversion flags deal with type conversions of individual array elements. The two data conversion flags, CoerceNumericToType and InputDateFormat, govern how numeric and date types are converted from VB to MATLAB. Consider this example:

• Sub foo( )
     Dim aClass As mycomponent.myclass
     Dim var1, var2 As Variant
     Dim y As Variant
     
     On Error Goto Handle_Error
     var1 = 1
     var2 = 2#
     Set aClass = New mycomponent.myclass
     Call aClass.foo(1,y,var1,var2)
     Exit Sub
  Handle_Error:
     MsgBox(Err.Description)
  End Sub
  

This example converts var1 of type Variant/Integer to an int16 and var2 of type Variant/Double to a double. If the original MATLAB function expects doubles for both arguments, this code might cause an error. One solution is to assign a double to var1, but this may not be possible or desirable. In such a case set the CoerceNumericToType flag to mwTypeDouble, causing the data converter to convert all numeric input to double. In the previous example, place the following line after creating the class and before calling the methods.

• aClass .MWFlags.DataConversionFlags.CoerceNumericToType = 
  mwTypeDouble
  

The InputDateFormat flag controls how the VB Date type is converted. This example sends the current date and time as an input argument and converts it to a string.

• Sub foo( )
     Dim aClass As mycomponent.myclass
     Dim today As Date
     Dim y As Variant
     
     On Error Goto Handle_Error
     today = Now
     Set aClass = New mycomponent.myclass
     aClass. MWFlags.DataConversionFlags.InputDateFormat = 
  mwDateFormatString
     Call aClass.foo(1,y,today)
     Exit Sub
  Handle_Error:
     MsgBox(Err.Description)
  End Sub
  

The next example uses an MWArg object to modify the conversion flags for one argument in a method call. In this case the first output argument (y1) is coerced to a Date, and the second output argument (y2) uses the current default conversion flags supplied by aClass.

• Sub foo(y1 As Variant, y2 As Variant)
      Dim aClass As mycomponent.myclass
      Dim ytemp As MWArg
      Dim today As Date
  
      On Error Goto Handle_Error
      today = Now
      Set aClass = New mycomponent.myclass
      Set y1 = New MWArg
      y1.MWFlags.DataConversionFlags.OutputAsDate = True
      Call aClass.foo(2, ytemp, y2, today)
      y1 = ytemp
      Exit Sub
  Handle_Error:
      MsgBox(Err.Description)
  End Sub
  

Array Formatting Flags

Usage Examples