internal static LinqLambdaExpression CreateLambda(QueryExpression source, IEnumerable <KeyValuePair <QueryProperty, QueryConstantExpression> > keys)
{
ExceptionUtilities.CheckArgumentNotNull(source, "source");
ExceptionUtilities.CheckCollectionNotEmpty(keys, "keys");
QueryType parameterType;
if (source.ExpressionType.IsUnresolved)
{
parameterType = QueryType.Unresolved;
}
else
{
var queryCollectionType = source.ExpressionType as QueryCollectionType;
ExceptionUtilities.CheckObjectNotNull(queryCollectionType, "Source expression type was not a collection. Type was: {0}", source.ExpressionType);
parameterType = queryCollectionType.ElementType;
}
var parameter = LinqBuilder.Parameter(ParameterName, parameterType);
// specifically using the overload of .Property which takes a type because it may have already been resolved and we don't want to throw that away
var predicate = keys.Select(k => parameter.Property(k.Key.Name, k.Key.PropertyType).EqualTo(k.Value)).ToList();
QueryExpression body = predicate[0];
if (predicate.Count > 1)
{
for (int i = 1; i < predicate.Count; i++)
{
body = CommonQueryBuilder.And(body, predicate[i]);
}
}
return(LinqBuilder.Lambda(body, parameter));
}
/// <summary>
/// Ensures that the given parameter has a name and creates a new instance if not.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns>Parameter with a name.</returns>
/// <remarks>Subsequent calls to this method with the same expression
/// will return the same instance of parameter.</remarks>
public LinqParameterExpression EnsureParameterHasName(LinqParameterExpression expression)
{
LinqParameterExpression parameterWithName;
if (!this.parameterMappings.TryGetValue(expression, out parameterWithName))
{
if (expression.Name == null)
{
parameterWithName = LinqBuilder.Parameter(this.parameterNameGenerator.GenerateIdentifier("p"), expression.ExpressionType);
}
else
{
parameterWithName = expression;
}
this.parameterMappings.Add(expression, parameterWithName);
}
return(parameterWithName);
}
private LinqLambdaExpression ResolveLambdaTypes(LinqLambdaExpression lambda, params QueryCollectionType[] parameterCollectionTypes)
{
ExceptionUtilities.Assert(lambda.Parameters.Count == parameterCollectionTypes.Length, "Lambda expression parameter numbers must match the length of parameterCollectionTypes.");
for (int i = 0; i < lambda.Parameters.Count; i++)
{
var lambdaParameter = lambda.Parameters[i];
this.parameterMappings.Add(lambdaParameter, LinqBuilder.Parameter(lambdaParameter.Name, parameterCollectionTypes[i].ElementType));
}
try
{
return((LinqLambdaExpression)this.ResolveTypes(lambda));
}
finally
{
foreach (var p in lambda.Parameters)
{
this.parameterMappings.Remove(p);
}
}
}
