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Please use our Code Center to obtain source-code and example projects/solutions:
http://codecenter.softwaretoolbox.com
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OPC Browsing
Be sure to check out the OPC Browser Tutorial.
This page shows you how to:
- Browse available PC's
- Browse available OPC Servers (using the dialog and via code)
- Browse available OPC Groups/Branches (via code)
- Browse available OPC Tags (using the dialog and via code)
 Browsing available PCs
try
{
//create a new browser object
OPCUserBrowseMachineClass o = new OPCUserObjects.OPCUserBrowseMachine();
//run the browser dialog
o.RunMe();
//check the result of the dialog
if(o.MachineName.Equals(""))
{
MessageBox.Show("No computer selected!");
}
else
{
MessageBox.Show(o.MachineName.ToString());
}
}
catch(Exception ex)
{
MessageBox.Show("Error: " + ex.Message.ToString());
}
Browsing Available OPC Servers
Via Dialog Browser
try
{
//define a browser object
OPCUserBrowseServerClass o = new
OPCUserBrowseServerClass();
//run the dialog
o.MachineName = "";
o..RunMe();
//now to see what the user did with the dialog
if(o.MachineName.Equals("") && o.ServerClass.Equals(""))
{
MessageBox.Show("Nothing selected!");
}
else
{
MessageBox.Show(o.MachineName + " - " + o.ServerClass);
}
}
catch(Exception ex)
{
MessageBox.Show("Error: {0}", ex.Message.ToString());
}
Via Code
The following code assumes that an empty for exists with a single listbox control in it. Place the following code in the Form_load event:
try
{
//'create the opc web client object
OPCLabs.EasyOPCDANet.EasyDACOM o = new OPCLabs.EasyOPCDANet.EasyDACOM();
//create a dictionary
//and make the call to get the opc servers list
string strMachineName = "127.0.0.1"
IDictionary serverElements = o.BrowseServers(strMachineName, null);
//now iterate thru the collection
foreach(object item in serverElements.Values)
{
//convert the item into a more usable object
OPCLabs.EasyOPCDANet.IServerElementNet svr = (OPCLabs.EasyOPCDANet.IServerElementNet)item;
//add the item to the listbox
listBox1.Items.Add(svr
.ProgID);
}
}
catch(Exception ex)
{
if(!(ex.InnerException == null))
{
MessageBox.Show("Error: " +
ex.InnerException.Message.ToString());
}
else
{
MessageBox.Show("Error: " + ex.Message.ToString());
}
}
Browsing Available OPC Groups/Branches
The following code assumes that an empty form exists with a single listbox control in it. Place the following code in the Form_load event:
try
{
// define an instance of the opc web client
OPCLabs.EasyOPCDANet.EasyDACOM EasyDA = new OPCLabs.EasyOPCDANet.EasyDACOM();
string strMachineName = ""; //name of the computer to browse
// define an object to receive the branches
// and make the call to read the branches
System.Collections.IDictionary BranchElements =
EasyDA.BrowseBranches
(
strMachineName,
"OPCLabs.KitServer.2",
"",
System.Reflection.Missing.Value,
System.Reflection.Missing.Value,
null
);
//now iterate thru our collection
foreach(object key in BranchElements.Values)
{
//convert the element into a usable object
OPCLabs.EasyOPCDANet.INodeElementNet be = (OPCLabs.EasyOPCDANet.INodeElementNet)key;
//is this object a branch?
if(be.IsBranch)
{
//yes: add it to the listbox
listBox1.Items.Add(be.Name.ToString());
}
}
//MessageBox.Show("Hello");
}
catch(Exception ex)
{
MessageBox.Show("Error: " + ex.Message.ToString());
}
Browsing Available Tags
Via Dialog Browser
try
{
//create a browser object
OPCUserBrowseItemClass o = new
OPCUserObjects.OPCUserBrowseItemClass();
//set the server and computer to browse
o.ServerClass = "OPCLabs.KitServer.2";
o.MachineName = "127.0.0.1";
//run the dialog
o.RunMe();
//now to see what the user picked
if(o.ItemID.Equals(""))
{
MessageBox.Show("Nothing selected!");
}
else
{
MessageBox.Show("Tag: " + o.ItemID.ToString());
}
}
catch(Exception ex)
{
MessageBox.Show("Error: " + ex.Message.ToString());
}
Via Code
The following code assumes that an empty for exists with a single listbox control in it. Place the following code in the Form_load event:
private void button1_Click(object sender,System.EventArgs e)
{
listBox1.Items.Clear();
listBox1.Items.Add("Please wait...");
try
{
//create a webclient object
OPCLabs.EasyOPCDANet.EasyDACOM objOWC = new
OPCLabs.EasyOPCDANet.EasyDACOM();
//create a dictionary object for the leaves
IDictionary leafElements;
//set the name of the computer to browse on
string strMachineName = "127.0.0.1";
/*now make the call to get the leaves for the "Simulation"
* branch within the greenhouse opc server*/
leafElements = objOWC.BrowseLeafs(strMachineName,
"OPCLabs.KitServer.2", "Simulation", null, null, null);
/*now clear the listbox because we are about to
* populate it*/
listBox1.Items.Clear();
//now iterate thru our collection
foreach(OPCLabs.EasyOPCDANet.INodeElementNet key in leafElements.Values)
{
//now to add into listbox
listBox1.Items.Add("Tag: " + key.Name.ToString()
+ ", ItemID: " + key.ItemID.ToString());
}
}
catch(Exception ex)
{
MessageBox.Show(ex.Message.ToString());
}
}
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