TexBox user Input to Hex Value

So I've got this form that a user puts in a numeric value into a text box. This value then has to be placed into a byte string of data so that it can be transmitted over as a packet. Bellow is what I have so far:

Code:

Byte[] OUTBuffer = new byte[65];	//Allocate output memory buffer
Byte[] INBuffer = new byte[65];    //Allocate input memory buffer

if (setmSpeed == true)
                        {
                            OUTBuffer[0] = 0;        //Not used, must be set to 0                          
                            OUTBuffer[1] = 0x85;   //Command mode
 
                            int decValue = Convert.ToInt32(textBox4.Text);  //Get textbox contents and vconvert it to an integer
                            byte[] intBytes = BitConverter.GetBytes(decValue);
                            OUTBuffer[2] = decValue;   //Data to be sent 

                            for (uint i = 3; i < 65; i++)	 //Set rest of data bytes to 1.
                            OUTBuffer[i] = 0xFF;		

                            WriteFile(WriteHandleToUSBDevice, OUTBuffer, 65, ref BytesWritten, IntPtr.Zero);	//Blocking function, unless an "overlapped" structure is used
                            ToggleLEDsPending = false;
                        }

I've put in red the area where I'm having issues. I've tried different methods and have not been able to get this working yet. It only works if I speciffy the value manually as with OUTBuffer[1] = 0x85;, but I want byte 2 of OUTBuffer[] to be set with what I put in the text box. Hope this is understandable, any help will be appreciated.

Isn't outbuffer[2] supposed to take intbytes?

YeWS

If you're sure the input value will fit in a single byte, then why are you converting it to an int? You can replace the entire red section with just this:

Code:

OUTBuffer[2] = Convert.ToByte(textBox4.Text);

If it doesn't fit in a single byte, then you'll have to copy all of the bytes instead of just one.

Code:

int decValue = Convert.ToInt32(textBox4.Text);
byte[] intBytes = BItConverter.GetBytes(decValue);
Array.Copy(intBytes, 0, OUTBuffer, 2, intBytes.Length);

And then you'd have to change your for() loop of course. Your comment says you're setting the rest of the bytes to 1, but 0xFF isn't 1...:

Code:

for(int i = 2 + intBytes.Length;i < 65;++i)
    OUTBuffer[i] = 0xFF;

Originally Posted by itsme86

If you're sure the input value will fit in a single byte, then why are you converting it to an int? You can replace the entire red section with just this:

Code:

OUTBuffer[2] = Convert.ToByte(textBox4.Text);

If it doesn't fit in a single byte, then you'll have to copy all of the bytes instead of just one.

Code:

int decValue = Convert.ToInt32(textBox4.Text);
byte[] intBytes = BItConverter.GetBytes(decValue);
Array.Copy(intBytes, 0, OUTBuffer, 2, intBytes.Length);

And then you'd have to change your for() loop of course. Your comment says you're setting the rest of the bytes to 1, but 0xFF isn't 1...:

Code:

for(int i = 2 + intBytes.Length;i < 65;++i)
    OUTBuffer[i] = 0xFF;

Very nice thanks. I'm more of an Electrical guy and been learning C# little by little.

Thanks. I'm now able to control the stepper motor over usb using the C# app I've made. You also answered what was going to be my next question about if the input value wouldn't fit into a single byte thanks for your help, this will help a lot in the long run.