SumHandleRead Class

Inheritance Hierarchy

System.Object
  SumCommandBase
    SumRead
      TwinCAT.Ads.SumCommand.SumHandleRead
Namespace: TwinCAT.Ads.SumCommand
Assembly: TwinCAT.Ads (in TwinCAT.Ads.dll) Version: 6.0.328+39e3229

C#

public class SumHandleRead : SumRead

The SumHandleRead type exposes the following members.

Methods

	Name	Description
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	Read	Reads the values.
	ReadAsync	Read the values asynchronously.
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	TryRead	Tries to read the values of the .

Remarks

This is an ADS Sum Command to access values by handle information. It is always used in combination with and . By design (and in contrast to the symbolic access in SumRead, SumSymbolWrite) this access method can act only with ADS ANY Type (Primitive) values (disadvantage). The Advantage is, that no symbolic information must be loaded before accessing the values, see samples:

Usage of Sum commands with handles (CreateHandles, Read, Write, ReleaseHandles)

/// <summary>
/// Defines the entry point of the application.
/// </summary>
/// <param name="args">The arguments.</param>
static async void Main(string[] args)
{
    Console.WriteLine("");
    Console.WriteLine("Press [Enter] for start:");
    Console.ReadLine();

    // Parse the command-line arguments
    AmsAddress address = ArgParser.Parse(args);

    CancellationTokenSource cancelSource = new CancellationTokenSource();
    CancellationToken cancel = cancelSource.Token;

    using (AdsClient client = new AdsClient())
    {
    // Connect the AdsClient to the device target.
    client.Connect(address);

    string[] instancePathList = {
        "GVL.bVar",
        "GVL.iCount",
        "TwinCAT_SystemInfoVarList._AppInfo.ProjectName"
    };
    SumCreateHandles createHandlesCommand = new SumCreateHandles(client,instancePathList);

    var resultCreateHandles = await createHandlesCommand.CreateHandlesAsync(cancel);

    if (resultCreateHandles.Succeeded)
    {
        uint[] handles = resultCreateHandles.Handles;
        Type[] valueTypes = new Type[]
        {
        typeof(bool),
        typeof(short),
        typeof(string)
        };
        SumHandleRead readCommand = new SumHandleRead(client, handles, valueTypes);
        var resultRead = await readCommand.ReadAsync(cancel);

        if (resultRead.Succeeded)
        {
        object[] readValues = resultRead.Values;

        for (int i = 0; i < instancePathList.Length; i++)
        {
            Console.WriteLine("Symbol: {0} (Value: {1}, Type: {2})", instancePathList[i], readValues[i].ToString(), valueTypes[i].Name);
        }

        // Sum Command Write
        SumHandleWrite writeCommand = new SumHandleWrite(client, handles, valueTypes);
        object[] writeValues = new object[] { true, (short)42, "MyNewProjectName" };

        await writeCommand.WriteAsync(writeValues,cancel);
        }

        SumReleaseHandles releaseCommand = new SumReleaseHandles(client, handles);
        await releaseCommand.ReleaseHandlesAsync(cancel);
    }
    }

    Console.WriteLine("");
    Console.WriteLine("Press [Enter] for leave:");
    Console.ReadLine();
}

Reference

TwinCAT.Ads.SumCommand Namespace

TwinCAT.Ads.SumCommand.SumCreateHandles

TwinCAT.Ads.SumCommand.SumReleaseHandles

TwinCAT.Ads.SumCommand.ISumCommand