DataGridView renders float number improperly?

I have a column of float number in my SQL server table, before inserting data into that table, I use cast() and round() to truncate any digits which are too far from the decimal point, for example 7.6899999999999995 should be rounded and casted to float type as 7.69, the combination of these functions work perfectly and when I view all the rows from that table by query in SQL Management studio, all the values in the column of float type are OK, but when I load that table into a dataset and display data using a datagridview, there are some values becoming 'original' like as they had never been rounded, the value 7.69 in my database becomes 7.6899999999999995 in my datagridview, that's so ugly and not what I want.

Could you please give me any reason for this and suggest me with some solution? I'm stuck at this totally.

Your help would be highly appreciated!
Thanks!

Tags: C#, Windows Forms