/// <summary>
/// Casts result of monitoring and reading values
/// </summary>
/// <param name="value">Value to convert</param>
/// <param name="casted">The casted result</param>
/// <typeparam name="T">Type of object to try to cast</typeparam>
public void TryCastResult <T>(object value, out T casted)
{
try
{
casted = (T)ConvertToT.ConvertT <T>(value);
}
catch (InvalidCastException ex)
{
throw new InvalidCastException(
string.Format(
"Could not monitor tag. Cast failed for type \"{0}\" on the new value \"{1}\" with type \"{2}\". Make sure tag data type matches.",
typeof(T), value, value.GetType()));
}
}
/// <summary>
/// Read a tag
/// </summary>
/// <typeparam name="T">The type of tag to read</typeparam>
/// <param name="tag">The fully-qualified identifier of the tag. You can specify a subfolder by using a comma delimited name.
/// E.g: the tag `foo.bar` reads the tag `bar` on the folder `foo`</param>
/// <returns>The value retrieved from the OPC</returns>
public T Read <T>(string tag)
{
var nodesToRead = BuildReadValueIdCollection(new string[] { tag }, Attributes.Value);
DataValueCollection results;
DiagnosticInfoCollection diag;
_session.Read(
requestHeader: null,
maxAge: 0,
timestampsToReturn: TimestampsToReturn.Neither,
nodesToRead: nodesToRead,
results: out results,
diagnosticInfos: out diag);
var val = results[0];
CheckReturnValue(val.StatusCode);
return((T)ConvertToT.ConvertT <T>(val.Value));
}
