You can build an expression tree which contains a continue statement using Expression.Continue method. For example, you have the following code.
int cValue = 0;
while (true)
{
cValue++;
if (cValue < 5)
{
if (cValue == 3)
{
continue;
}
else
{
Console.WriteLine(cValue);
}
}
else
{
break;
}
}
Here is the code that is required to build the same functionality using expression tree.
LabelTarget breakLabel = Expression.Label();
// A label that is used by the Continue statement and the loop it refers to.
LabelTarget continueLabel = Expression.Label();
// This expression represents a Continue statement.
Expression continueExpr = Expression.Continue(continueLabel);
// A variable that triggers the exit from the loop.
ParameterExpression count = Expression.Parameter(typeof(int));
var ifTrueBlock = continueExpr;
var ifFalseBlock = Expression.Call(
null,
typeof(Console).GetMethod("WriteLine", new Type[] { typeof(int) }),
count
);
var nestedIfThenElseExpr = Expression.IfThenElse(
Expression.Equal(count, Expression.Constant(3)),
ifTrueBlock,
ifFalseBlock
);
var ifThenElseExpr = Expression.IfThenElse(
Expression.LessThan(count, Expression.Constant(5)),
nestedIfThenElseExpr,
Expression.Break(breakLabel, count)
);
var block = Expression.Block(Expression.PostIncrementAssign(count), ifThenElseExpr);
// A loop statement.
Expression loopExpr = Expression.Loop(block,
breakLabel,
continueLabel
);
Expression.Lambda<Action<int>>(loopExpr, count).Compile()(0);