Cannot implicitly convert string to CBCharacteristic? - ios

Question

public void GrantLocalUARTCredits()
{
if (this.PendingLocalUARTCreditsCount != 0) return;
this.PendingLocalUARTCreditsCount = this.MaxLocalUARTCreditsCount -
this.LocalUARTCreditsCount;
Byte[] byteData = new Byte[1];
byteData[0] = (Byte)((this.PendingLocalUARTCreditsCount & 0xFF));
NSData valueData = (NSData.FromArray(byteData));
Characteristic UartRxCreditsCharacteristic = "00000003-0000-1000-
8000-008025000000";(error here)
this.CbPeripheral.WriteValue(valueData, this.UartRxCreditsCharacteristic, CBCharacteristicWriteType.WithoutResponse);
}
I'm using CoreBluetools in a xamarin C# project and
get null reference exception with the last line as the CBCharacteristic I think is not defined. At the top of the file I define CBCharacteristic with
public CBCharacteristic UartRxCreditsCharacteristic {get ; set;}
and in this file below this I set the uuid with
public static string UART_RX_CREDITS_UUID = " 00000003-0000-1000-8000-008025000000"
I can discover,connect and disconnect with the app as it worked with our original device but with this device it requires RX/TX credits to communicate (1 credit for each 20 byte packet max 255 credits). This bit of code is from the original translated Objective C (to C#) manufacturers code and the error is the WriteValue code line says 'Null reference Exception'((object reference not set to an instance of an object) as I think the Characteristic can't be found when I run the code. enter code here
Not sure how to solve this. Nick

Answer 1

This code does the trick
internal void Connect(CBPeripheral peripheral)
{
peripheral.DiscoveredService += (sender, e) =>
{
if (peripheral.Services == null) { return; }
foreach (var s in peripheral.Services)
// var s in peripheral.Services
{
//if (s.UUID.ToString().Contains("0000f100"))
if (s.UUID.ToString().Contains("fefb"))
//s = s.UUID.ToString();
{
service = s;
peripheral.DiscoverCharacteristics(service);
};
}
};
peripheral.DiscoveredCharacteristic += (sender, e) =>
{
foreach (var c in service.Characteristics)
{
if (c.UUID.ToString() == (TIO_UART_RX_UUID))
{
UartRxCharacteristic = c;
}
}
foreach (var c in service.Characteristics)
{
if (c.UUID.ToString() == (TIO_UART_RX_CREDITS_UUID))
{
UartRxCreditsCharacteristic = c;
}
}
foreach (var c in service.Characteristics)
{
if (c.UUID.ToString() == (TIO_UART_TX_CREDITS_UUID))
{
UartTxCreditsCharacteristic = c;
peripheral.SetNotifyValue(true, c);
}
}
foreach (var c in service.Characteristics)
{
if (c.UUID.ToString() == (TIO_UART_TX_UUID))
// {