How to Convert a Byte Array to String for a DataGridView

Question

I have a Domain Class User with the Following properties (Fields):

UserId (int)
UserName (nvarchar(25))
SecurePassword (varbinary(32))
Salt (varbinary(32))

SecurePassword and Salt store a byte array with a length of 32 as you may have guessed. If I set my

BindingSource.DataSource = context.Users.Local.ToBindingList();

And then my

DataGridView.DataSource = BindingSource;

I’ll get an Error telling me to Handle the DataError Event for the GridView. Once I do that with an empty method the SecurePassword and Salt Columns show [X] for every row.

Now, I could use linq to render that in an anonymous type as:

 var data = from u in context.Users
            select new
            {
                u.UserId,
                u.UserName,
                SecurePassword = BitConverter.ToString(u.SecurePassword),
                Salt = BitConverter.ToString(u.Salt)
            };

But I really don’t want an anonymous type. In WPF I could have written a Converter that inherits from IValueConverter, but that doesn’t seem to be available in WinForms. Any help would be greatly appreciated and welcomed.

Answer 1

Use CellFormatting event. Something like:

void dataGridView_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    // 2 - Salt, 3 - SecurePassword
    if (e.ColumnIndex == 2 || e.ColumnIndex == 3)
    {
        if (e.Value != null)
        {
            byte[] array = (byte[])e.Value;
            e.Value = BitConverter.ToString(array);
            e.FormattingApplied = true;
        }
        else
            e.FormattingApplied = false;
    }
}

Answer 2

To build upon the other answer, the simplest way I achieved this was:

1. Go into Properties of your DataGridView, find the Columns property, edit it, and change the ColumnType of your binary columns to DataGridViewTextBoxColumn.
2. Go into the Events pane and generate a method on the CellFormatting event.
3. Set the code of the method to be something like:

---

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    if (e.ColumnIndex == 1 || e.ColumnIndex == 2)
    {
        if (e.Value != null)
        {
            e.Value = Encoding.UTF8.GetString((byte[]) e.Value);
            e.FormattingApplied = true;
        }
        else
            e.FormattingApplied = false;
    }
}