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Gets the actually read value or sets the value of the processvariable depending on the WriteValueAutomatic property(Event: ValueWritten)

[Visual Basic]

<CLSCompliant(IsCompliant:=False)> _

Public Property Value() As Value

  Public Get

  End Get

  Public Set

  End Set

End Property

[C#]

[CLSCompliant(IsCompliant=False)]

public Value Value { public get; public set; }

Remarks

Accessing values (writing or reading) is raised always by the variable object which is located on the left side from the ".Value["..."]" property call. For this reason it is not possible to set the value of a structure member on the plc by doing something like this:

   // Creating a new structur variable
Variable stVar = new Variable(cpuObj,"stVar");
stVar.Connect();
...
...
// After Connected Event was raised
Variable tmpMember = stVar["subSt.subElem_1"];
tmpMember.Value = 23; // This does not work, because the "tmpMember" is not connected.
   // Connecting the "tmpMember" object makes value accessing possible.

This works:

stVar.Value["subSt.subElem_1"] = 23;

Example

This example describes using the ValueChanged event for structure variables

 // Setting variable values:
 Variable var = new Variable(cpuObj,"globVar");
 var.Connect();
 var.Value = 22.45;
 // Setting structure member values:
 Variable structVar = new Variable(cpuObj,"stVar");
 structVar.Connect();
 structVar.WriteValueAutomatic = false;
 // Setting member values
 structVar.Value["elem_BOOL"] = true;
 structVar.Value["elem_SINT"] = 15;
 structVar.Value["elem_DINT"] = 345578;
 // Writing whole structure
 structVar.WriteValue();
 structVar.WriteValueAutomatic = true;
 //Reading values from structure elements using ValueChanged event
 Variable structVar = new Variable(cpuObj,"stVar");
 structVar.Connect();
 structVar.Active = true;
 structVar.ValueChanged += new VariableEventHandler(Var_ValueChanged);
 ...
 ...
 private void Var_ValueChanged(object sender, VariableEventArgs e)
 {
        Variable tmpVar = (Variable)sender;
        if (mpVar.Value.DataType == DataType.Structure )
        {
            // Iterating ChangedMembers property
            foreach ( String strVar in e.ChangedMembers )
            {
                // Accessing values by string index -> tmpVar.Value["subSt.subElem_INT"]
                labelValueText.Text = tmpVar.Value[strVar].ToString();
            }
        }
        ...
        ...
 }

This example describes value accessing on variables of type structure.

// Creating a new variable which describes a structure with arraylenght 5 on the plc
// (object"cpuObj" already connected)
Variable structArr = new Variable(cpuObj,"stArray");
// Creating a new variable which describes a simple structure on the plc
Variable structSimple = new Variable(cpuObje,"struct");
// Connecting each variable object
struct.Connect();
structArr.Connect();
// Adding handler to Connected events
struct.Connected +=new PviEventHandler(struct_Connected);
structArr.Connected +=new PviEventHandler(structArr_Connected);
...
...
private void struct_Connected(object sender, PviEventArgs e)
{
       // Reading values from structure variables by using the string indexer
       Int32 myValue=null;
       Variable tmpVar = (Varialbe)sender;
       // Reading value from an element
       myValue = tmpVar.Value["elem_1"];
       // Reading value from a subelement
       myValue = tmpVar.Value["elem_2.subElem_1"];
       // Reading value from a subelement which arraylength is 5
       myValue = tmpVar.Value["elem_2.subElem_2[4]"];
}
...
...
// Reading values from variable objects of type structure which arraylength is bigger than 1
// requires an expansion of the string indexer. For that it is necessary to insert the name
// of the structure array + the indexer in brackets before the "normal" indexer string.
private void structArr_Connected(object sender, PviEventArgs e)
{
       // Reading values from structure array variables by using the string indexer
       Int32 myValue=null;
       Variable tmpVar = (Varialbe)sender;
       // Reading value from an element
       myValue = tmpVar.Value["stArray[0].elem_1"];
       // Reading value from a subelement
       myValue = tmpVar.Value["stArray[1].elem_2.subElem_1"];
       // Reading value from a subelement which arraylength is 5
       myValue = tmpVar.Value["stArray[2].elem_2.subElem_2[4]"];
}

See Also

Variable Class | BR.AN.PviServices Namespace

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