OPCUA探讨（四）——客户端代码解读2 - ToB企服应用市场:ToB评测及商务社交产业平台

public virtual ResponseHeader Browse(
RequestHeader requestHeader, //*客户端请求报文的头部，可为null
ViewDescription view, //*所浏览的视图的ID，可为null
NodeId nodeToBrowse, //所浏览的节点ID
uint maxResultsToReturn, //最大返回结果数目
BrowseDirection browseDirection, //浏览方向（正向浏览子节点/反向浏览父节点）
NodeId referenceTypeId, //浏览的引用类型ID，即要浏览哪类引用
bool includeSubtypes, //是否包括子类型
uint nodeClassMask, //对查询结果的节点类进行筛选
out byte[] continuationPoint, //接续点，由于OPCUA报文长度限制，服务器可能不会一次返回所有浏览结果（太长），通过接续点再次发送请求可以继续获取剩余的浏览结果（服务器返回）
out ReferenceDescriptionCollection references //返回浏览到的引用信息集合（服务器返回）
)

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/// <summary>
/// 浏览节点
/// 通过nodeId遍历其子节点（根节点nodeId=""）
/// 反向获取父节点时inverse=true
/// </summary>
/// <param name="nodeId">想要浏览的节点的ID</param>
/// <param name="inverse">是否反向浏览</param>
/// <returns></returns>
public ReferenceDescriptionCollection Browse(string nodeId="",bool inverse=false)
{
if (current_session == null) //浏览功能建立在会话的基础上
return null;
if (current_session.Connected == false)//浏览功能建立在会话连接的基础上
return null;
ReferenceDescriptionCollection referenceDescriptionCollection; //当前获取到的子节点的信息
byte[] continuationPoint; //接续点。由于OPCUA报文长度限制，服务器可能不会一次返回所有浏览结果（太长），通过接续点再次发送请求可以继续获取剩余的浏览结果
if (nodeId == "") //nodeId为空时，默认浏览根节点
{
current_session.Browse(
null, //requestHeader
null, //ViewDescription view
ObjectIds.RootFolder, //NodeId-根目录
0u, //maxResultToReturn
BrowseDirection.Forward, //正向-遍历子节点（反向Inverse-回溯父节点）
ReferenceTypeIds.HierarchicalReferences, //NodeId ReferenceTypeId
true, //includeSubtypes
(uint)NodeClass.Variable | (uint)NodeClass.Object | (uint)NodeClass.Method, //nodeClassMask
out continuationPoint, //byte[] continuationPoint（用于获取后续结果）
out referenceDescriptionCollection
); //references
}
else if(inverse == true) //反向查询父节点
{
//MessageBox.Show(nodeId);
current_session.Browse(null, null,
nodeId,
1, //仅返回一个引用（父节点就一个）
BrowseDirection.Inverse, //反向查询标志
ReferenceTypeIds.HierarchicalReferences,
true,
0,
out continuationPoint,
out referenceDescriptionCollection);
}
else //正向查询子节点
{
ReferenceDescriptionCollection nextreferenceDescriptionCollection; //当前获取到的子节点的信息
byte[] revisedContinuationPoint; //接续点，用于获取后续结果
current_session.Browse(
null,
null,
nodeId,
0u,
BrowseDirection.Forward,
ReferenceTypeIds.HierarchicalReferences,
true,
0,//不进行nodeClass筛选
out continuationPoint,
out referenceDescriptionCollection
);
while (continuationPoint != null)//循着起始点遍历全部子节点
{
current_session.BrowseNext(null, false, continuationPoint, out revisedContinuationPoint, out nextreferenceDescriptionCollection);//继续浏览下一个节点，返回的nextreferenceDescriptionCollection为所需信息
referenceDescriptionCollection.AddRange(nextreferenceDescriptionCollection);
continuationPoint = revisedContinuationPoint;//更新
}
}
return referenceDescriptionCollection;
}

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/// <summary>
/// 获取某个节点的详细信息
/// </summary>
/// <param name="refDesc">节点描述信息，用于读取详细信息</param>
/// <returns></returns>
public object[] GetNodeInfo(ReferenceDescription refDesc)
{
if(refDesc==null)
{
return null;
}
object[] rows=null;
Node node = current_session.ReadNode(refDesc.NodeId.ToString());
//节点值需要单独获取，使用ReadValue函数
string value = this.ReadValue(refDesc.NodeId.ToString());
try
{
VariableNode variableNode = new VariableNode();
string[] rowx = new string[] { "节点值", value };
string[] row1 = new string[] { "节点类", refDesc.NodeClass.ToString() };
string[] row2 = new string[] { "节点ID", refDesc.NodeId.ToString() };
string[] row3 = new string[] { "命名空间索引", refDesc.NodeId.NamespaceIndex.ToString() };
string[] row4 = new string[] { "Identifier Type", refDesc.NodeId.IdType.ToString() };
string[] row5 = new string[] { "Identifier", refDesc.NodeId.Identifier.ToString() };
string[] row6 = new string[] { "浏览名称", refDesc.BrowseName.ToString() };
string[] row7 = new string[] { "显示名称", refDesc.DisplayName.ToString() };
string[] row8 = new string[] { "描述", "null" };
if (node.Description != null)
{
try { row8 = new string[] { "Description", node.Description.ToString() }; }
catch { row8 = new string[] { "Description", "null" }; }
}
string typeDefinition = "";
if ((NodeId)refDesc.TypeDefinition.NamespaceIndex == 0)
{
typeDefinition = refDesc.TypeDefinition.ToString();
}
else
{
typeDefinition = "Struct/UDT: " + refDesc.TypeDefinition.ToString(); //类型为结构体或数据表
}
string[] row9 = new string[] { "类型定义", typeDefinition };
string[] row10 = new string[] { "Write Mask", node.WriteMask.ToString() };
string[] row11 = new string[] { "User Write Mask", node.UserWriteMask.ToString() };
if (node.NodeClass == NodeClass.Variable)
{
variableNode = (VariableNode)node.DataLock;
List<NodeId> nodeIds = new List<NodeId>();
IList<string> displayNames = new List<string>();
IList<ServiceResult> errors = new List<ServiceResult>();
NodeId nodeId = new NodeId(variableNode.DataType);
nodeIds.Add(nodeId);
current_session.ReadDisplayName(nodeIds, out displayNames, out errors);
int valueRank = variableNode.ValueRank;
List<string> arrayDimension = new List<string>();
string[] row12 = new string[] { "数据类型", displayNames[0] };
string[] row13 = new string[] { "Value Rank", valueRank.ToString() };
//Define array dimensions depending on the value rank
if (valueRank > 0) //More dimensional arrays
{
for (int i = 0; i < valueRank; i++)
{
arrayDimension.Add(variableNode.ArrayDimensions.ElementAtOrDefault(i).ToString());
}
}
else
{
arrayDimension.Add("标量");
}
string[] row14 = new string[] { "数组维数", String.Join(";", arrayDimension.ToArray()) };
string[] row15 = new string[] { "访问级别", variableNode.AccessLevel.ToString() };
string[] row16 = new string[] { "最小采样间隔", variableNode.MinimumSamplingInterval.ToString() };
string[] row17 = new string[] { "历史化", variableNode.Historizing.ToString() };
rows = new object[] { rowx, row1, row2, row3, row4, row5, row6, row7, row8, row9, row10, row11, row12, row13, row14, row15, row16, row17 };
}
else
{
rows = new object[] { rowx, row1, row2, row3, row4, row5, row6, row7, row8, row9, row10, row11 };
}
//MessageBox.Show(refDesc.ToString());
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error");
}
return rows;
}
/// <summary>
/// 读取节点的值（Value）
/// 根据节点ID，读取节点变量值
/// </summary>
/// <param name="nodeIdString"></param>
/// <returns></returns>
public string ReadValue(string nodeIdString)
{
NodeId nodeId=new NodeId(nodeIdString);
//MessageBox.Show(nodeIdString);
try
{
var res = current_session.ReadValue(nodeId);
if (res != null)
{
if (res.Value != null)
{
return res.Value.ToString();
}
}
}
catch(Exception ex)
{
return "null";
}
return "";
}

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