'The given key was not present in the dictionary' - 但密钥存在

Question

我目前正在开发 MS Dynamics CRM 2013 - 插件。当我尝试将字符串值分配给实体字段的键时，它给了我 'keynotfound'-exception。

这让我毫无头绪，因为我可以验证密钥是否存在。我给的key也写对了，数据类型也兼容

这里有一些额外的信息：

我尝试通过重新启动服务器来解决问题。没有。
远程调试不是一个选项。
我用 retrieved.EntityCollection.Entities[i]["new_name"] 交换了 "retrieved.EntityCollection.Entities[i][forField]"，一切正常（这里有点明显，但 "new_name" 不是我尝试访问的密钥）。
执行停止@"if (retrieved.EntityCollection.Entities[i][forField].ToString() != "" && !overwriteExisting)"

你有什么想法可以帮助我吗？

public void GenerateNumberForEntityCollection(string target)
{
    try
    {
        // variables for number generation
        bool overwriteExisting = (bool)preImageEntity["new_overwriteexisting"];
        int suffixstart = (int)preImageEntity["new_suffixstart"];
        string forField= preImageEntity["new_forfield"].ToString();
        string prefix = preImageEntity["new_prefix"].ToString();
        string postfix = preImageEntity["new_postfix"].ToString();
        string separator = preImageEntity["new_separator"].ToString();

        // Build query to get all the entries
        RetrieveMultipleResponse retrieved;
        int PageNumber = 1;
        string PagingCookie = string.Empty;
        int PageSize = 5000;
        string[] Columns = { forField };
        QueryExpression query = new QueryExpression()
        {
            EntityName = target,
            ColumnSet = new ColumnSet(Columns),
            PageInfo = new PagingInfo()
            {
                PageNumber = 1,
                Count = PageSize
            }
        };

        do
        {
            if (PageNumber != 1)
            {
                query.PageInfo.PageNumber = PageNumber;
                query.PageInfo.PagingCookie = PagingCookie;
            }

            RetrieveMultipleRequest retrieve = new RetrieveMultipleRequest();
            retrieve.Query = query;
            retrieved = (RetrieveMultipleResponse)service.Execute(retrieve);

            // Now that all entities are retrieved, iterate through them to gen. the numbers
            int i = 0;
            foreach (Entity entity in retrieved.EntityCollection.Entities)
            {
                if (retrieved.EntityCollection.Entities[i][forField].ToString() != "" && !overwriteExisting)
                {
                    //continue;
                }
                else
                {
                    retrieved.EntityCollection.Entities[i][forField] = prefix + separator + suffixstart.ToString() + separator + postfix;
                }
                suffixstart++;
                service.Update(retrieved.EntityCollection.Entities[i]);
                i++;
            }
            if (retrieved.EntityCollection.MoreRecords)
            {
                PageNumber++;
                PagingCookie = retrieved.EntityCollection.PagingCookie;
            }
        } while (retrieved.EntityCollection.MoreRecords);
    }
    catch (Exception e)
    {
        tracing.Trace("GenerateNumberForEntityCollection: Failed: {0}", e.ToString());
    }
}

Answer 1

你是如何验证密钥存在的？

如果 字段中的数据为 null，实体实例 将不包含该键 ，即使您在查询的列集。

这将为您 return 一个布尔值，指示该键是否存在于实体中。您可以在尝试读取属性之前执行此控制。

var attributeExists = retrieved.EntityCollection.Entities[i].Contains(forField)

如果该字段为空，您所做的下面的控制将导致您得到的异常。只要确保该属性之前存在即可。

retrieved.EntityCollection.Entities[i][forField].ToString() != ""

~~此外，如果查询中没有记录 return，您将得到空引用异常。让你对 retrieved.EntityCollection.Entities.~~

进行空检查

Answer 2

当您在 Dynamics CRM 中查询数据时，请务必了解数据库中具有 null 值的记录字段不包含在 Entity 实例的 Attributes 集合中被退回。

使用此构造从 Entity 的 Attribute 获取值：

var value = retrieved.EntityCollection.Entities[i][forField].ToString();

当属性 forField 已在数据库中具有值时成功，但当其当前值为 null.

时失败

因此，从实体获取属性值的首选方法是 GetAttributeValue<T>，如下所示：

var value = retrieved.EntityCollection.Entities[i].getAttributeValue<string>(forField);

此方法returns当属性存在于属性集合中时取值，否则returnsnull.

Answer 3

If any of the fields among (new_forfield,new_prefix,new_postfix,new_separator) has null value, that column does not present in the retrieved object and you are trying to get the value of null column preImageEntity["new_forfield"] which will throw keynotfound'-exception ,
so change the code

string forField= preImageEntity["new_forfield"].ToString();
string prefix = preImageEntity["new_prefix"].ToString();
string postfix = preImageEntity["new_postfix"].ToString();
string separator = preImageEntity["new_separator"].ToString();

至

string forField = preImageEntity.Attributes.Contains("new_forfield")? preImageEntity["new_forfield"].ToString():"";
string prefix = preImageEntity.Attributes.Contains("new_forfield") ? preImageEntity["new_prefix"].ToString() : "";
string postfix = preImageEntity.Attributes.Contains("new_forfield") ? preImageEntity["new_postfix"].ToString() : "";
string separator = preImageEntity.Attributes.Contains("new_forfield") ? preImageEntity["new_separator"].ToString() : "";

this will check for field, if it exists than will parse the value to string else will assign empty string.

'The given key was not present in the dictionary' - 但密钥存在

'The given key was not present in the dictionary' - but the key exists

c#

dynamics-crm

dynamics-crm-2013

keynotfoundexception