| public Update ( Expression expression ) : MemberExpression | ||
| expression | Expression | The |
| Результат | MemberExpression | |
/// <summary>
/// Visits the children of the <see cref="MemberExpression" />.
/// </summary>
/// <param name="node">The expression to visit.</param>
/// <returns>
/// The modified expression, if it or any subexpression was modified;
/// otherwise, returns the original expression.
/// </returns>
protected internal virtual Expression VisitMember(MemberExpression node)
{
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
return(node.Update(Visit(node.Expression)));
}
protected override Expression VisitMember(MemberExpression memberExpression)
{
var newExpression = Visit(memberExpression.Expression);
var subQueryExpression = newExpression as SubQueryExpression;
var subSelector = subQueryExpression?.QueryModel.SelectClause.Selector;
if (subSelector is QuerySourceReferenceExpression
|| subSelector is SubQueryExpression)
{
var subQueryModel = subQueryExpression.QueryModel;
subQueryModel.SelectClause.Selector = VisitMember(memberExpression.Update(subSelector));
subQueryModel.ResultTypeOverride = subQueryModel.SelectClause.Selector.Type;
return new SubQueryExpression(subQueryModel);
}
return memberExpression.Update(newExpression);
}
protected override Expression VisitMember(MemberExpression m)
{
Expression source = this.Visit(m.Expression);
switch (source.NodeType)
{
case ExpressionType.Call:
MethodCallExpression call = (MethodCallExpression)source;
if (call != null && call.Method.Name == "NewDefaultProjectedObject")
{
var bindings = ((ConstantExpression)call.Arguments[0]).Value as ReadOnlyCollection<MemberBinding>;
for (int i = 0, n = bindings.Count; i < n; i++)
{
MemberAssignment assign = bindings[i] as MemberAssignment;
if (assign != null && MembersMatch(assign.Member, m.Member))
{
return assign.Expression;
}
}
}
break;
case ExpressionType.MemberInit:
MemberInitExpression min = (MemberInitExpression)source;
for (int i = 0, n = min.Bindings.Count; i < n; i++)
{
MemberAssignment assign = min.Bindings[i] as MemberAssignment;
if (assign != null && MembersMatch(assign.Member, m.Member))
{
return assign.Expression;
}
}
break;
case ExpressionType.New:
NewExpression nex = (NewExpression)source;
if (nex.Members != null)
{
for (int i = 0, n = nex.Members.Count; i < n; i++)
{
if (MembersMatch(nex.Members[i], m.Member))
{
return nex.Arguments[i];
}
}
}
break;
}
return m.Update(source);
}
protected override ExpressionTree VisitMember(MemberExpression node)
{
MemberExpression expression;
if (node.Expression != null)
{
CheckChildrenCount(1);
var e = ExtractChildExpression(0);
expression = node.Update(e);
}
else
{
CheckChildrenCount(0);
expression = node;
}
return(CreateExpressionTree(expression));
}
/// <summary>
/// Visits the children of the <see cref="MemberExpression"/>.
/// </summary>
/// <param name="node">The expression to visit.</param>
/// <returns>The modified expression, if it or any subexpression was modified;
/// otherwise, returns the original expression.</returns>
protected internal virtual Expression VisitMember(MemberExpression node)
{
return(node.Update(Visit(node.Expression)));
}
/// <summary>
/// Visits a member expression with the specified <paramref name="isLval"/> behavior.
/// See <see cref="VisitMember(MemberExpression)"/> for more information about visitor behavior.
/// </summary>
/// <param name="node">The member expression to visit.</param>
/// <param name="isLval">Indicates whether the member expression occurs in an assignment target position.</param>
/// <returns>The result of visiting the member expression.</returns>
protected virtual Expression VisitMember(MemberExpression node, bool isLval)
{
var expression = isLval ? VisitLval(node.Expression) : Visit(node.Expression);
return(node.Update(expression));
}
