failed to create a sytem.windows. style. from text to none

[kumar p]

hi ,

  i am getting an  exception not able to figure it  out.

for the expand and collapse button  in data grid

if (row.DetailsVisibility == Visibility.Visible)

{

row.DetailsVisibility = Visibility.Collapsed;

} else

{

row.DetailsVisibility = Visibility.Visible;

// here i am getting an exception.

}

 failed  to create a sytem.windows. style.  from text  to none

 xaml code

 

   <Button x:Name="btn"  
   Click="Expand3_Click"    >
    <Image  x:Name="img1" Source="Images/a1.jpg" Stretch="None" />
       </Button> 

any  help  would be greatly appreciated.