Question

How to convert XString passed from DeviceDriver.c to String.

 

When I pass XString from DeviceDriver.c to UI It will not show, it shows blank. When I pass int then it will work fine.

Answer 1

Hi unais,

If you work with a "String" in the GUI (Chora, within Embedded Wizard Studio) and you generate the code for C, it will create an XString as a representation of the String.

That means also (the other way around), if you pass an XString to GUI, it should end up with in a String.

Usually there are two use cases:

1. Function in DeviceDriver / C: Create XString in DeviceDriver and pass it to GUI:

void UpdateValue( char* aValue )
{
  XString valStr = EwNewStringAnsi( (char*)aValue );
  DeviceDeviceClass__UpdateString( DeviceObject, valStr );
}

Within the GUI, inside the DeviceClass there is a function UpdateString( string ), which is called via DeviceDriver.

 

2. Function in DeviceClass / Chora: Get String from device (e.g. middleware) and pass it to UI component:

GetStatus()
{
  // The variable should receive some device status information.
  var string status = "";

  $if !$prototyper
    native ( status )
    {
      char buf[256];
      int  voltage;
      int  current;
      
      /* Call some functions to get the status information of the device */
      voltage     = device_get_voltage();
      current     = device_get_current();
      
      /* Format a status message in the temporary buffer 'buf' */
      sprintf( buf, "STATUS: %d Centigrade, %d Volt, %d Ampere", voltage, current );
      
      /* From the ANSI string in 'buf' create Embedded Wizard string and
         return it in the variable 'status'.  */
      status = EwNewStringAnsi( buf );
    }
  $endif

  // 'status' contains now the message as a correct string.
  return status;
}

Within the GUI, inside the DeviceClass there is a function GetStatus(), which is called via GUI and grabs the strings from C, creates and returns an XString .

 

See also: https://doc.embedded-wizard.de/integrating-with-the-device?v=11.00#6

 

Hope this helps,
Chris

Comments

it worked ...

thanks for your help...