/// <summary>
/// Given a text expression and runtimeArgs, evaluate the expression.
/// Expressions must be compatible with DataColumn.Expression. the result is cast to T
/// </summary>
public static object EvaluateExpression(this WfExpression expression, IRunState run)
{
// Evaluate
try
{
var knownEntities = new Dictionary <string, Resource>();
using (new SecurityBypassContext())
{
// we need to fetch the known entities in a bypass so that the expression
// evaluation will trigger a security error rather than a missing entity.
foreach (var ke in expression.WfExpressionKnownEntities)
{
if (ke.ReferencedEntity != null && !string.IsNullOrEmpty(ke.Name))
{
if (knownEntities.ContainsKey(ke.Name))
{
knownEntities[ke.Name] = ke.ReferencedEntity;
}
else
{
knownEntities.Add(ke.Name, ke.ReferencedEntity);
}
}
}
}
var result = EvaluateExpressionImpl(expression, run, knownEntities);
return(result);
}
catch (ParseException ex)
{
throw new WorkflowExpressionEvaluationException(ex.ShortMessage, ex.ToString(), ex);
}
catch (Exception ex)
{
var sb = new StringBuilder();
// Format runtimeArgs
sb.AppendFormat("Error: {0}\n", ex.Message);
sb.AppendFormat("Expression: ** {0} **\n", expression.ExpressionString ?? "null");
sb.AppendFormat("Exception: {0}\n", ex.GetType().Name);
sb.AppendFormat("Expression ID: {0}\n", expression.Id);
sb.AppendFormat("isTemplate: {0}\n", expression.IsTemplateString == null ? "null" : expression.IsTemplateString.ToString());
sb.AppendFormat("target: {0}\n", expression.ArgumentToPopulate != null ? expression.ArgumentToPopulate.Id.ToString() : "null");
sb.AppendFormat("parameters: \n");
run.PrettyPrint(sb);
var activity = expression.ExpressionInActivity;
var workflowRunId = activity != null && activity.ContainingWorkflow != null ? activity.ContainingWorkflow.Id : 0;
var message = ex is PlatformSecurityException ? $"Expression failed with a security violation" : $"Expression failed during evaluation";
throw new WorkflowExpressionEvaluationException($"{message}: '{expression.ExpressionString ?? "Null"}'", sb.ToString(), ex);
}
}
private string GetStateString(IRunState runState)
{
try {
var sb = new StringBuilder();
runState.PrettyPrint(sb);
return(sb.ToString());
}
catch (Exception ex)
{
EventLog.Application.WriteError(ex.ToString());
return("Unable to retrieve workflow state information");
}
}