MVVM Light RelayCommand Parameters

I'm having an issue with passing a parameter to a relaycommand using the GalaSoft MVVM Light framework. I know that mvvm light's implementation of relaycommand doesn't use lambda parameters, so I did some research and found a way that people worked around it by doing something like this:

public RelayCommand ProjMenuItem_Edit
{
    get
    {
        if (_projmenuItem_Edit == null)
开发者_StackOverflow        {
            //This should work....
            _projmenuItem_Edit = new RelayCommand(ProjEditNode);
        }
        return _projmenuItem_Edit;
    }
}

private void ProjEditNode(object newText)
{
    var str = newText as string;
    OrganLocationViewModel sel = 
        ProjectOrganLocationView.GetExtendedTreeView().GetTopNode();

    //Console.WriteLine(sel.OrganDisplayName);
    sel.OrganDisplayName = str;
}

However, I keep getting an error on the line _projmenuItem_Edit = new RelayCommand(ProjEditNode); that says Argument 1: cannot convert from 'method group' to 'System.Action'

What am I missing?

I believe this will work:

_projmenuItem_Edit = new RelayCommand<object>((txt)=>ProjEditNode(txt));

-- EDIT --

You'll need to define your RelayCommand with the type as well:

e.g.

public RelayCommand<string> myCommand { get; private set; }
myCommand = new RelayCommand<string>((s) => Test(s));

private void Test(string s)
{
    throw new NotImplementedException();
}

I don't think that RelayCommand() has a constructor that is not empty. you're trying to pass the wrong kind of method to it.

If you want the RelayCommand to support Command Parameters, you should use RelayCommand<T> where T can be any type of parameter. In your situation it would be RelayCommand<String> which would accept a method with void(string) signature. (and therefor would also be strongly typed and won't use the ugly object)

Another way to declare relay commands, will help to reduce your code

public RelayCommand ChartCommand
{
    set
    {
        RelayCommand<string> chartCommand = 
            new RelayCommand<string>(e => ExecuteChartCommand(e));               
    }
}

public void ExecuteChartCommand(string vendor)
{

}