Merge pull request #93 from libplctag/overload-read-write

Overload Read/Write to actually use Value directly

README.md

@@ -59,11 +59,17 @@ var myTag = new TagDint()
 };
 
 // Read the value from the PLC
-myTag.Read();
-int output = myTag.Value;
+int output = myTag.Read();
 
 // Output to Console
-Console.WriteLine($"SomeProgram.SomeDINT = {output}");
+Console.WriteLine($"Original value: SomeProgram.SomeDINT = {output}");
+
+// Write a new value to the PLC then read it back
+myTag.Write(37);
+output = myTag.Read();
+
+// Output to Console
+Console.WriteLine($"Updated value: SomeProgram.SomeDINT = {output}");
 ```
 In advanced scenarios, tags can be instantiated using generics (ex. `Tag<DintPlcMapper, int>`, `Tag<BoolPlcMapper, bool>`) and can be referenced via an `ITag` interface.
 

src/Examples/CSharp DotNetCore/SimpleExample.cs

@@ -0,0 +1,40 @@
+using libplctag;
+using libplctag.DataTypes;
+using System;
+using System.Net;
+using System.Threading;
+
+namespace CSharpDotNetCore
+{
+    class SimpleExample
+    {
+        public static void Run()
+        {
+            //This is the absolute most simplified example code
+            //Please see the other examples for more features/optimizations
+
+            //Instantiate the tag with the proper mapper and datatype
+            var myTag = new Tag<DintPlcMapper, int>()
+            {
+                Name = "PROGRAM:SomeProgram.SomeDINT",
+                Gateway = "10.10.10.10",
+                Path = "1,0",
+                PlcType = PlcType.ControlLogix,
+                Protocol = Protocol.ab_eip,
+                Timeout = TimeSpan.FromSeconds(5)
+            };
+
+            //Write value to PLC
+            //This will call Initialize internally since it's the first use of this tag
+            //myTag.Value will be set to 3737 before being transferred to PLC
+            myTag.Write(3737);
+
+            //Read value from PLC
+            //Value will also be accessible at myTag.Value
+            int myDint = myTag.Read();
+
+            //Write to console
+            Console.WriteLine(myDint);
+        }
+    }
+}

src/libplctag/ITag.cs

@@ -23,9 +23,11 @@ public interface ITag : IDisposable
         Status GetStatus();
         void Initialize();
         Task InitializeAsync(CancellationToken token = default);
-        void Read();
-        Task ReadAsync(CancellationToken token = default);
+        object Read();
+        Task<object> ReadAsync(CancellationToken token = default);
         void Write();
         Task WriteAsync(CancellationToken token = default);
+
+        Object Value { get; set; }
     }
 }

src/libplctag/TagOfT.cs

@@ -132,19 +132,25 @@ public async Task InitializeAsync(CancellationToken token = default)
         }
 
         /// <inheritdoc cref="Tag.ReadAsync"/>
-        public async Task ReadAsync(CancellationToken token = default)
+        public async Task<T> ReadAsync(CancellationToken token = default)
         {
             await _tag.ReadAsync(token);
             DecodeAll();
+            return Value;
         }
 
         /// <inheritdoc cref="Tag.Read"/>
-        public void Read()
+        public T Read()
         {
             _tag.Read();
             DecodeAll();
+            return Value;
         }
 
+        object ITag.Read() => Read();
+
+        async Task<object> ITag.ReadAsync(CancellationToken token) => await ReadAsync();
+
         /// <inheritdoc cref="Tag.WriteAsync"/>
         public async Task WriteAsync(CancellationToken token = default)
         {
@@ -155,6 +161,13 @@ public async Task WriteAsync(CancellationToken token = default)
             await _tag.WriteAsync(token);
         }
 
+        /// <inheritdoc cref="Tag.WriteAsync"/>
+        public async Task WriteAsync(T value, CancellationToken token = default)
+        {
+            Value = value;
+            await WriteAsync(token);
+        }
+
         /// <inheritdoc cref="Tag.Write"/>
         public void Write()
         {
@@ -165,6 +178,13 @@ public void Write()
             _tag.Write();
         }
 
+        /// <inheritdoc cref="Tag.Write"/>
+        public void Write(T value)
+        {
+            Value = value;
+            Write();
+        }
+
         void DecodeAll()
         {
             Value = _plcMapper.Decode(_tag);
@@ -189,7 +209,7 @@ void EncodeAll()
         /// The local memory value that can be transferred to/from the PLC
         /// </summary>
         public T Value { get; set; }
-
+        object ITag.Value { get => Value; set => Value = (T)value; }
 
         public event EventHandler<TagEventArgs> ReadStarted
         {