Improve company productivity with a Business Account.Sign Up

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 417
  • Last Modified:

c# store function in list or call function by name

I have a list box and when I click on it, I fire off a function corresponding to that item.

so if I click "Order History" then function OrderHistory is called.  I do this by adding strings to the listbox, then having a case statement and test the string and call a function.  I'd rather add a string and a function to some list and call it a better way.  It would save me typing

something like
List<string, function>functions;

functions.add("Order History", OrderHistory());

execute(string functionname)
functions...somehow call that function

This is basically a cheap rip off of a command pattern that I used.  this is just for one testing form and i want it to be easy.
0
jackjohnson44
Asked:
jackjohnson44
  • 3
  • 3
2 Solutions
 
Vel EousResearch & Development ManagerCommented:
Perhaps something like the following (bit rough and ready):

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Windows;
using System.Windows.Controls;

namespace Sandbox.wpf
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs args)
        {
            var selected = (sender as ListBox).SelectedItems;
            if (selected.Count > 0)
            {
                foreach (var item in selected)
                {
                    string functionToExecute = (item as ListBoxItem).Content.ToString();
                    Console.WriteLine(functionToExecute);
                    MethodInfo method = this.GetType().GetMethod(functionToExecute);
                    object result = method.Invoke(this, new object[] { "Hello World" });
                }
            }
        }

        public bool Function1(string str)
        {
            MessageBox.Show(str);
            return true;
        }

        public bool Function2(string str)
        {
            MessageBox.Show(str);
            return true;
        }
    }
}

Open in new window

0
 
jackjohnson44Author Commented:
Thanks!  I am having an issue though.  For some reason, my GetMethod is always null.

        private void Calling()
        {
             //always null
            MethodInfo method = this.GetType().GetMethod("FunctionToCall");
            object result = method.Invoke(this, null);
        }
        private void FunctionToCall()
        {
            MessageBox.Show("It Works");
        }
0
 
Vel EousResearch & Development ManagerCommented:
The GetMethod function can only reflect on public methods.
0
What Kind of Coding Program is Right for You?

There are many ways to learn to code these days. From coding bootcamps like Flatiron School to online courses to totally free beginner resources. The best way to learn to code depends on many factors, but the most important one is you. See what course is best for you.

 
käµfm³d 👽Commented:
The GetMethod function can only reflect on public methods.
I don't believe that's accurate.

I don't see the need for Reflection here. Just populate your list box with the delegates you want to invoke.

e.g.

using System;
using System.Windows.Forms;

namespace _28132404
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.listBox1.Items.Add(new ListItem() { DisplayValue = "Run Func1", FuncToInvoke = Func1 });
            this.listBox1.Items.Add(new ListItem() { DisplayValue = "Run Func2", FuncToInvoke = Func2 });
            this.listBox1.Items.Add(new ListItem() { DisplayValue = "Run Func3", FuncToInvoke = Func3 });
        }

        private void Func1()
        {
            MessageBox.Show("Hello World!");
        }

        private void Func2()
        {
            MessageBox.Show("Weather's nice today.");
        }

        private void Func3()
        {
            MessageBox.Show("Goodbye world!");
        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (this.listBox1.SelectedItem != null)
            {
                ListItem item = this.listBox1.SelectedItem as ListItem;

                if (item != null)
                {
                    item.FuncToInvoke();
                }
            }
        }
    }

    public class ListItem
    {
        public string DisplayValue { get; set; }
        public Action FuncToInvoke { get; set; }

        public override string ToString()
        {
            return this.DisplayValue;
        }
    }
}

Open in new window

0
 
Vel EousResearch & Development ManagerCommented:
I don't believe that's accurate.

You're correct, I completely forgot about and forgot to check its overloads.  Thanks for pointing that out.

http://msdn.microsoft.com/en-us/library/system.type.getmethod(v=vs.110).aspx
0
 
jackjohnson44Author Commented:
Thanks guys, one more question though.

How can i split up the step so that i create a list bind the listbox to it?

I don't want to:
this.listBox1.Items.Add(new ListItem() { DisplayValue = "Run Func1", FuncToInvoke = Func1 });
0
 
jackjohnson44Author Commented:
Thanks, I went with this:
        private Dictionary<string, Action> actions = new Dictionary<string, Action>();

            actions.Add("Log Me In", Login);

             actions[commandName].Invoke();
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

What Kind of Coding Program is Right for You?

There are many ways to learn to code these days. From coding bootcamps like Flatiron School to online courses to totally free beginner resources. The best way to learn to code depends on many factors, but the most important one is you. See what course is best for you.

  • 3
  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now