为了使用 SOAP 端点获取实体的所有元数据，您可以使用 RetrieveEntityRequest：
var request = new RetrieveEntityRequest
{
EntityFilters = Microsoft.Xrm.Sdk.Metadata.EntityFilters.All,
LogicalName = "account"
}
var response = (RetrieveEntityResponse)organizationService.Execute(request);
EntityFiters 是一个枚举，它允许您指定要获取的元数据：
[Flags]
public enum EntityFilters
{
//
// Summary:
// Use this to retrieve only entity information. Equivalent to EntityFilters.Default.
// Value = 1.
Entity = 1,
//
// Summary:
// Use this to retrieve only entity information. Equivalent to EntityFilters.Entity.
// Value = 1.
Default = 1,
//
// Summary:
// Use this to retrieve entity information plus attributes for the entity. Value
// = 2.
Attributes = 2,
//
// Summary:
// Use this to retrieve entity information plus privileges for the entity. Value
// = 4.
Privileges = 4,
//
// Summary:
// Use this to retrieve entity information plus entity relationships for the entity.
// Value = 8.
Relationships = 8,
//
// Summary:
// Use this to retrieve all data for an entity. Value = 15.
All = 15
}
这是一个标志枚举，所以你可以这样使用它：
var request = new RetrieveEntityRequest
{
EntityFilters = EntityFilters.Privileges | EntityFilters.Entity,
LogicalName = "account"
}
或者简单地使用All 值来获取所有必要的元数据。在您的尝试中，您未能检索到元数据，因为您只询问了实体元数据并且您对属性元数据感兴趣。
因此，以您的代码 sn-p 为基础，我将按以下方式使用它：
[Route("Account", Name = "CreateAccount", Order = 1)]
[HttpPost]
public Account CreateAccount([FromBody] Account account)
{
VerifyRequiredFields(account);
var newAccount = _accountService.CreateAccountEntity(account);
return newAccount;
}
private void VerifyRequiredFields(Account account)
{
var response = GetEntityMetadata(account);
var requiredAttributes = response.EntityMetadata.Attributes.Where(a => a.RequiredLevel?.Value == AttributeRequiredLevel.SystemRequired);
foreach(var requiredAttribute in requiredAttributes)
{
if(CheckIfValueIsProvided(requiredAttribute.LogicalName, account))
{
throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest, $"You are missing required value {requiredAttribute.LogicalName}"));
}
}
}
方法GetEntityMetadata 只是做前面例子中的事情，所以调用RetrieveEntityRequest 并返回RetrieveEntityResponse。
当然，方法CheckIfValueIsProvided 的实现取决于您的 Account 模型类的定义方式，但您可能需要在模型和 CRM 实体模型之间进行某种映射（了解如何将例如字段“accountnumber”映射到某个字段在您的模型中）。这远远超出了这个问题的范围，但我相信你已经足够了解了。
请记住，这只是一个例子。您不应该将此逻辑保留在您的控制器类中，您应该将其移动到可以在不同控制器中重用的某个实用程序类中。元数据不会经常更改（并且您可能可以控制这些更改），因此您可能还希望将元数据缓存在 Web 应用程序等的某个位置。我希望您已经知道可以做什么，但是整个设计如果逻辑是另一个故事。
如果您想通过 JavaScript 执行此操作，您可能应该坚持使用 webAPI：
http://CRMADDRESS/api/data/v8.2/EntityDefinitions(LogicalName='account')/Attributes?$select=LogicalName,RequiredLevel
将为您提供所需的内容（属性名称及其必需级别）。它看起来像这样：
{
"LogicalName":"preferredcontactmethodcodename","RequiredLevel":{
"Value":"None","CanBeChanged":false,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"8663b910-af86-4dea-826e-8222706372f4"
},{
"@odata.type":"#Microsoft.Dynamics.CRM.StringAttributeMetadata","LogicalName":"emailaddress3","RequiredLevel":{
"Value":"None","CanBeChanged":true,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"97fb4aae-ea5d-427f-9b2b-9a6b9754286e"
},{
"@odata.type":"#Microsoft.Dynamics.CRM.StringAttributeMetadata","LogicalName":"emailaddress2","RequiredLevel":{
"Value":"None","CanBeChanged":true,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"98b09426-95ab-4f21-87a0-f6775f2b4210"
},{
"@odata.type":"#Microsoft.Dynamics.CRM.StringAttributeMetadata","LogicalName":"emailaddress1","RequiredLevel":{
"Value":"None","CanBeChanged":true,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"b254ab69-de5a-4edb-8059-bdeb6863c544"
},{
"@odata.type":"#Microsoft.Dynamics.CRM.StringAttributeMetadata","LogicalName":"masteraccountidyominame","RequiredLevel":{
"Value":"None","CanBeChanged":false,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"a15dedfc-9382-43ac-8d10-7773aa3eefeb"
},{
"@odata.type":"#Microsoft.Dynamics.CRM.StringAttributeMetadata","LogicalName":"address1_city","RequiredLevel":{
"Value":"None","CanBeChanged":true,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"ca8d0a94-8569-4154-b511-718e11635449"
},{
"@odata.type":"#Microsoft.Dynamics.CRM.LookupAttributeMetadata","LogicalName":"slaid","RequiredLevel":{
"Value":"None","CanBeChanged":true,"ManagedPropertyLogicalName":"canmodifyrequirementlevelsettings"
},"MetadataId":"6bdcd7f1-5865-4fef-91b0-676824b18641"
}
您可以使用它来验证客户端的请求，在用户向服务器发送请求之前提示他丢失了重要数据。