Performing a Mouse Click Without Moving Cursor

Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type

The problem is that topAgents is dynamic - so your ToList() call is dynamic, and so is Select. That has issues that:

1. you can't use lambda expressions for dynamic calls like this;
2. dynamic calls don't find extension methods anyway.

Fortunately, the operations don't need to be dynamic just because the element type is dynamic. You could use:

IEnumerable<dynamic> topAgents = ...;

... or just use var. Both of those should be fine.

Cannot use a lambda expression as an argument to a dynamically dispatched operation Kendo ListView

 @(Html.Kendo().ListView<Entity.Models.DocViewModel>()
     .Name("listView")
            .TagName("div")
            .ClientTemplateId("DocumentList")

    )

Nevermind, I had a syntax error.

Cannot use a lambda expression as an argument to a dynamically dispatched

The error message is pretty clear I think.

An anonymous lambda can represent a delegate (and there can be many matching delegate types) or an expression tree. It does not have a type by itself until assigned to a variable of specific type or, used in a context where a specific type is expected. When regular (non-dynamic) types are used the compiler can usually deduce target type (such as Func<string, string>). When dynamic types are involved though - compiler cannot do that, because all resolutions are now performed at runtime, not at compile time. So compiler will not assign type Func<string, dynamic, dynamic> to your lambda and you should do it yourself (as compiler suggests):

cache.AddOrUpdate(key, value, (Func<string, dynamic, dynamic>) ((k, v) => value));

Example here.

error CS1977: Cannot use a lambda expression as an argument to a dynamically dispatched operation

Using a foreach and creating a parameterized SqlCommand is best practice

var ds = (JArray)o["Tables"][0]["Rows"];

using (var connection = new SqlConnection(cnnString)) {
    connection.Open();
    var cmdIns = new SqlCommand("INSERT INTO dbo.AddPlay(UserId, Timestamp, YoutubeId, Source, PlayCount, Rating) VALUES(@UserId, @Timestamp, @YoutubeId, @Source, @PlayCount, @Rating)", connection);
    cmdIns.Parameters.Add("@UserId", SqlDbType.VarChar, 20);
    cmdIns.Parameters.Add("@Timestamp", SqlDbType.VarChar, 20);
    cmdIns.Parameters.Add("@YoutubeId", SqlDbType.VarChar, 20);
    cmdIns.Parameters.Add("@Source", SqlDbType.VarChar, 20);
    cmdIns.Parameters.Add("@PlayCount", SqlDbType.Int);
    cmdIns.Parameters.Add("@Rating", SqlDbType.Int);

    foreach (var ja in ds) {
        cmdIns.Parameters["@UserId"].Value = ja[0].Value<string>();
        cmdIns.Parameters["@Timestamp"].Value = ja[1].Value<string>();
        cmdIns.Parameters["@YoutubeId"].Value = ja[2].Value<string>();
        cmdIns.Parameters["@Source"].Value = ja[3].Value<string>();
        cmdIns.Parameters["@PlayCount"].Value = GetInt(ja[4]);
        cmdIns.Parameters["@Rating"].Value = GetInt(ja[5]);

        cmdIns.ExecuteNonQuery();
    }
}

ASP.NET MVC: Cannot use a lambda expression as an argument to a dynamically dispatched operation

It looks like you're doing this in your view, which violates the principles of separation of concerns. But this is how you would do it.

@
{
   var layers = Model.layers.Where(x => x.KONT == "EUROPE").ToList();
}

@foreach(var layer in layers)
{
  .....
}

A Better Way

What you should do however is create a method on your Model "GetLayersForLocation" Then your code would look like this:

In Your Model Class

public IEnumerable<Layer> GetLayersForLocation(string location)
{
    return this.layers.Where(x => x.Knot == location);
}

In Your View Code

@foreach(var layer in Model.GetLayersForLocation("EUROPE"))
{
  .....
}

The reason this is better is you can now unit test your code, before you wouldn't be able to because it's just part of your view, but now you can run automated tests to ensure that getting the proper layers is working.

MatchEvaluator gives Cannot use a lambda expression... error

You are replacing the contents of DBText. Regex.replace expectes a string as first argument. I am guessing DBText is of type dynamic, which confuses the compiler in this particular case.

You can simply cast DbText to string and you should be fine

patternURL.Replace((string)DBText, (...)

Error passing both a dynamic object and an Action to a function

Sure - do exactly as the compiler says - cast the lambda expression to a concrete type:

Calc(obj, (Action<int>)(result => Console.Write("Result: " + result)));

The reason you have to do this is that a lambda expression doesn't have a type - the compiler has to know what delegate (or expression tree) type you're trying to convert it to. It can't do that if the method you'll be calling won't be chosen until execution time, which is the case when another argument is dynamic.

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