C# OPCUA 读写结构体

OPCUA结构体的读写说白了就是对ExtensionObject中按规则对byte的转换

读取步骤：

1.首先可以先用UAExpert查看结构体

2.读取出结构体DataValue的值

3.把读取出来的值转换成ExtensionObject[]

4.把ExtensionObject中每项进行解析。

具体步骤解析：

1.首先可以先用UAExpert查看

如图1我们能看到有一个结构体的数据类型ExtensionObject。这个结构体的有5项，且每个字段都是什么。（这里主要验证我们后期自己读取的数据对不对）

图1

2.读取出结构体DataValue的值

这里我们通过session中的ReadValue()方法读取出结构体DataValue的值，这里和正常的已知nodeID读值方法一样（怎么建立连接，大家可以搜随便搜一下就能找到，或者也可以看我前面OPCUA的文章）。

           DataValue item= m_session.ReadValue(new NodeId(ItemAdress));

3.把读取出来的值转换成ExtensionObject[]

读取后我们可以看到value的值，如图2，它是一个ExtensionObject类型长为100的数据。而且每项都是byte[]，我们要做的就是如何把byte按照规则转换成字符

4.把ExtensionObject中每项进行解析。

首先我们先得到ExtensionObject中的结构体的项，下面代码中typeDefine中就能看到结构体中的所有项，大家可以打个断点看看

            NodeId node = new NodeId(ItemAdress);//获取Node 信息 验证Node的数据类型VariableNode nodeInfo = m_session.ReadNode(node) as VariableNode;//DataValue value = m_session.ReadValue(node);var datatypeNode = (m_session.ReadNode(nodeInfo.DataType)) as DataTypeNode;var typeDefine = datatypeNode.DataTypeDefinition.Body as StructureDefinition;

然后就是遍历所有项，其中GetJsonFromExtensionObject就是对每项就行解析

            if (value.Value is ExtensionObject[])//数组{JArray res = new JArray();foreach (var item in value.Value as ExtensionObject[]){res.Add(GetJsonFromExtensionObject(item, typeDefine,ref index));}return res.ToString();}

最后对每项项进行解析时，要和相关人员确定byte[]拼接的规则。比如我这里如果该项是字符串，那么首先需要先读取该字符串所占的长度，然后根据长度读取字符串。当然具体项目中的规则也可能不完全相同，但是思路是一样的。如果是int,float直接读取4个byte，bool读取1个byte,double读取8个byte,根据一个类型占多少位决定。下面代码可供参考

        private JObject GetJsonFromExtensionObject(ExtensionObject value, StructureDefinition structure,ref int index){JObject res = new JObject();var data = value.Body as byte[];foreach (var field in structure.Fields){if (field.DataType.NamespaceIndex==2){var count = BitConverter.ToUInt32(data.Skip(index).Take(4).ToArray(), 0);index += 4;var datatypeNode1 = (m_session.ReadNode(field.DataType)) as DataTypeNode;var typeDefine = datatypeNode1.DataTypeDefinition.Body as StructureDefinition;for (int i = 0; i < count; i++){res[field.Name+i] =GetJsonFromExtensionObject(value, typeDefine,ref index);}}string name = field.Name;if (field.DataType == DataTypeIds.String){int length = (int)BitConverter.ToUInt32(data.Skip(index).Take(4).ToArray(), 0);//读取字符串所占长度index += 4;string re = Encoding.Default.GetString(data.Skip(index).Take(length).ToArray());//根据字符串长度读取字符串res[name] = re;index += length;}if (field.DataType == DataTypeIds.UInt32){UInt32 re = BitConverter.ToUInt32(data.Skip(index).Take(4).ToArray(), 0);index += 4;res[name] = re;}if (field.DataType == DataTypeIds.Float){float re = BitConverter.ToSingle(data.Skip(index).Take(4).ToArray(), 0);index += 4;res[name] = re;}if (field.DataType == DataTypeIds.Boolean){bool re = BitConverter.ToBoolean(data.Skip(index).Take(1).ToArray());res[name] = re;index += 1;}if (field.DataType == DataTypeIds.Double){double re = BitConverter.ToDouble(data.Skip(index).Take(8).ToArray());res[name] = re;index += 8;}}return res;}

读取结构体完整代码如下：

public string structItem(string ItemAdress){DataValue item= m_session.ReadValue(new NodeId(ItemAdress));string aaa = ReadStruct(ItemAdress, item);return aaa;}/// <summary>/// 读取结构体数据/// </summary>public string ReadStruct(string ItemAdress, DataValue value){#region 得到ExtensionObject中的结构体的项NodeId node = new NodeId(ItemAdress);//获取Node 信息 验证Node的数据类型VariableNode nodeInfo = m_session.ReadNode(node) as VariableNode;//DataValue value = m_session.ReadValue(node);var datatypeNode = (m_session.ReadNode(nodeInfo.DataType)) as DataTypeNode;var typeDefine = datatypeNode.DataTypeDefinition.Body as StructureDefinition;#endregionint index = 0;if (value.Value is ExtensionObject[])//数组{JArray res = new JArray();foreach (var item in value.Value as ExtensionObject[]){res.Add(GetJsonFromExtensionObject(item, typeDefine,ref index));}return res.ToString();}else //非数组{return GetJsonFromExtensionObject(value.Value as ExtensionObject, typeDefine, ref index).ToString();}}private JObject GetJsonFromExtensionObject(ExtensionObject value, StructureDefinition structure,ref int index){JObject res = new JObject();var data = value.Body as byte[];foreach (var field in structure.Fields){if (field.DataType.NamespaceIndex==2){var count = BitConverter.ToUInt32(data.Skip(index).Take(4).ToArray(), 0);index += 4;var datatypeNode1 = (m_session.ReadNode(field.DataType)) as DataTypeNode;var typeDefine = datatypeNode1.DataTypeDefinition.Body as StructureDefinition;for (int i = 0; i < count; i++){res[field.Name+i] =GetJsonFromExtensionObject(value, typeDefine,ref index);}}string name = field.Name;if (field.DataType == DataTypeIds.String){int length = (int)BitConverter.ToUInt32(data.Skip(index).Take(4).ToArray(), 0);//读取字符串所占长度index += 4;string re = Encoding.Default.GetString(data.Skip(index).Take(length).ToArray());//根据字符串长度读取字符串res[name] = re;index += length;}if (field.DataType == DataTypeIds.UInt32){UInt32 re = BitConverter.ToUInt32(data.Skip(index).Take(4).ToArray(), 0);index += 4;res[name] = re;}if (field.DataType == DataTypeIds.Float){float re = BitConverter.ToSingle(data.Skip(index).Take(4).ToArray(), 0);index += 4;res[name] = re;}if (field.DataType == DataTypeIds.Boolean){bool re = BitConverter.ToBoolean(data.Skip(index).Take(1).ToArray());res[name] = re;index += 1;}if (field.DataType == DataTypeIds.Double){double re = BitConverter.ToDouble(data.Skip(index).Take(8).ToArray());res[name] = re;index += 8;}}return res;}

写入步骤：

1.首先可以先用UAExpert查看结构体

2.把每项的结构体转成把ExtensionObject,加入到ExtensionObject[]

3.把ExtensionObject[]写入即可

写入结构体的难点就是如何按照规则（就是拼接方式）把结构体转成byte[]然后加入到ExtensionObject[]

1.首先可以先用UAExpert查看结构体

同读取，省略

2.把每项的结构体转成把ExtensionObject,加入到ExtensionObject[]

首先定义一个结构体类，同UAExpert查看结构体，注意结构体顺序也不能乱

    /// <summary>/// writevar对象/// </summary>public class WriteVar{/// <summary>/// 数组索引/// </summary>public int index = 0;/// <summary>/// 数据项名称/// </summary>public string Name = "";/// <summary>/// 数据类型/// </summary>public int DataType = 0;/// <summary>/// 字符串值/// </summary>public string StringValue = "";/// <summary>/// 整数值/// </summary>public int IntValue = 0;/// <summary>/// 浮点数值/// </summary>public float FloatValue = 0.0F;}

然后赋值给结构体，并转成ExtensionObject，这里我定义的规则就是如果是字符串就要把长度也拼接上

            WriteVar structs = new WriteVar{index = 4,Name = "重量",DataType = 0,StringValue = "",IntValue = 25,FloatValue = 0.0F};var result = Pro_OPCUA.GetValueByteFromObj(structs);/// <summary>/// 从对象中获取对象所有的值，并转化为byte[]/// </summary>/// <param name="value">需要写入节点的值组成的byte数组列表</param>/// <returns></returns>public static ExtensionObject GetValueByteFromObj(WriteVar value){List<byte> result = new List<byte>();//前4位为字符串数据长度var length = BitConverter.GetBytes(value.Name.Length);result.AddRange(length);//数据项名称var Name = Encoding.Default.GetBytes(value.Name);result.AddRange(Name);//数据类型var DataType = BitConverter.GetBytes(value.DataType);result.AddRange(DataType);//字符串数据转换if (value.StringValue.Length==0){result.AddRange(new byte[4] { 0,0,0,0});}else{//前4位为字符串数据长度length = BitConverter.GetBytes(value.StringValue.Length);result.AddRange(length);//字符串数据var StringValue = Encoding.Default.GetBytes(value.StringValue);result.AddRange(StringValue);}//整数数据var IntValue = BitConverter.GetBytes(value.IntValue);result.AddRange(IntValue);//浮点数数据var FloatValue = BitConverter.GetBytes(value.FloatValue);result.AddRange(FloatValue);return new ExtensionObject {Body= result.ToArray() } ;}

3.把ExtensionObject[]写入即可

其实拼接好ExtensionObject[]后按照通用写OPCUA的方法就可以了

        }/// <summary>/// OPCUATag写入/// </summary>/// <param name="value">需要写入节点的值组成的byte数组列表</param>/// <returns></returns>public void WriteVarStruct(ExtensionObject[] value,string nodeId){WriteValueCollection nodesToWrite = new WriteValueCollection();nodesToWrite.Add(new WriteValue(){NodeId = new NodeId(nodeId),AttributeId = Attributes.Value,Value = new DataValue(){Value = value}});WriteNode(nodesToWrite);}/// <summary>/// OPCUATag写入/// </summary>/// <param name="adress">需要写入节点的地址</param>/// <param name="value">需要写入节点的值</param>/// <returns></returns>public bool WriteNode(WriteValueCollection value){try{//if (isCconnect)//{StatusCodeCollection resultsValues = null;DiagnosticInfoCollection diagnosticInfos = null;//Console.WriteLine("数据读取开始");// Call Read Servicevar result = m_session.Write(null,value,out resultsValues,out diagnosticInfos);//写入返回值为bad，则写入失败if (StatusCode.IsBad(result.ServiceResult)){return false;}//验证结果ClientBase.ValidateResponse(resultsValues, value);return true;//}//return false;}catch (Exception ex){throw new Exception("OPUAReadNodes:" + ex.Message + ex.StackTrace);}}

写结构体的完整代码：

        private void button6_Click(object sender, EventArgs e){ExtensionObject[] AA = new ExtensionObject[100];for (int i = 0; i < AA.Length; i++){AA[i] = new ExtensionObject { Body = getNewByte() };}WriteVar structs = new WriteVar{index = 4,Name = "重量",DataType = 0,StringValue = "",IntValue = 25,FloatValue = 0.0F};var result = Pro_OPCUA.GetValueByteFromObj(structs);AA[4] = result;float a = 1.23F;WriteVar structs1 = new WriteVar{index = 5,Name = "形状",DataType = 1,StringValue = "",IntValue = 0,FloatValue = a};var result1 = Pro_OPCUA.GetValueByteFromObj(structs1);AA[5] = result1;WriteVar structs2 = new WriteVar{index = 6,Name = "C",DataType = 2,StringValue = "WUXE",IntValue = 0,FloatValue = 0.0F};var result2= Pro_OPCUA.GetValueByteFromObj(structs2);AA[6] = result2;//byte[] re = new byte[23] { 3,0,0,0,56,56,56,0,0,0,0,0,0,0,0,128,0,0,0,0,0,0,0};string aaa= AA.ToString();pro_OPCUAp.WriteVarStruct(AA, "ns=2;s=writeStrucat");}/// <summary>/// OPCUATag写入/// </summary>/// <param name="value">需要写入节点的值组成的byte数组列表</param>/// <returns></returns>public void WriteVarStruct(ExtensionObject[] value,string nodeId){WriteValueCollection nodesToWrite = new WriteValueCollection();nodesToWrite.Add(new WriteValue(){NodeId = new NodeId(nodeId),AttributeId = Attributes.Value,Value = new DataValue(){Value = value}});WriteNode(nodesToWrite);}/// <summary>/// OPCUATag写入/// </summary>/// <param name="adress">需要写入节点的地址</param>/// <param name="value">需要写入节点的值</param>/// <returns></returns>public bool WriteNode(WriteValueCollection value){try{//if (isCconnect)//{StatusCodeCollection resultsValues = null;DiagnosticInfoCollection diagnosticInfos = null;//Console.WriteLine("数据读取开始");// Call Read Servicevar result = m_session.Write(null,value,out resultsValues,out diagnosticInfos);//写入返回值为bad，则写入失败if (StatusCode.IsBad(result.ServiceResult)){return false;}//验证结果ClientBase.ValidateResponse(resultsValues, value);return true;//}//return false;}catch (Exception ex){throw new Exception("OPUAReadNodes:" + ex.Message + ex.StackTrace);}}

项目地址：

OPCUA读写结构体示例-C#文档类资源-CSDN文库