了解 Func 的 C# 方法<字典<字符串、实体属性>、字符串>

Question

我有来自不同来源的代码，目标是在CSV文件与定义的模式匹配后读取该文件，然后将其复制到表格数据库中。在将文件复制到表格数据库中之前，CSV文件必须具有以下两列：PartitionKey和RowKey。如果分区键不在那里，那么它应该将正在传递的ID作为参数。下面是代码，我不明白Func<Dictionary<>,string>部分在做什么。有人能向我解释一下它的用途和工作原理吗？

//主要函数WriteToTable的调用方式如下：

await WriteToTable(lines, dataclass,
p => documentId,
p => $"{dataclass.SubType}_{p["RowKey"].Int32Value.Value.ToString("D10")}", upsert);

//写入表

public async Task WriteToTable(string lines, DataClass dataclass,
Func<Dictionary<string, EntityProperty>, string> genPartitionKey,
Func<Dictionary<string, EntityProperty>, string> genRowKey, bool upsert)
{
const int BatchSize = 100;
if (HasPartitionAndRowKey(dataclass.TableSchema.Fields))
{
genPartitionKey = (Dictionary<string, EntityProperty> props) => props["PartitionKey"].StringValue;
genRowKey = (Dictionary<string, EntityProperty> props) => props["RowKey"].ToString();
}
var tableRecords =ReadCSV(lines, dataclass.TableSchema.Fields)
.Select(props => new DynamicTableEntity(genPartitionKey(props), genRowKey(props), string.Empty, props))
.ToList();
await batchInsertIntoTableStorage(BatchSize,tableRecords, upsert);

}
static readonly string[] RequiredTableKeys = { "PartitionKey", "RowKey" };
private bool HasPartitionAndRowKey(List<TableField> fields)
{
return fields.Select(f => f.Name).Intersect(RequiredTableKeys).Count() == RequiredTableKeys.Length;
}

Answer 1

这是函数如何工作的最简单方法

public bool Validate(Func<string,bool> dependentMethod)
{
string parmeter = "after execution inside method";
bool isvalid = dependentMethod(parmeter);
return isvalid;
}
public bool DependentMethod(string input)
{
// process  there statement and return out put after your business logics
return true;
}
public void CheckValidation()
{
bool isValid= Validate(DependentMethod);
}

根据您的方法

public async Task WriteToTable(string lines, DataClass dataclass,
Func<Dictionary<string, EntityProperty>, string> genPartitionKey,
Func<Dictionary<string, EntityProperty>, string> genRowKey, bool upsert)

这是你的方法头，这里有两个函数genPartitionKey，genRowKey

实施

if (HasPartitionAndRowKey(dataclass.TableSchema.Fields))
{
genPartitionKey = (Dictionary<string, EntityProperty> props) => props["PartitionKey"].StringValue;
genRowKey = (Dictionary<string, EntityProperty> props) => props["RowKey"].ToString();
}

如果check为true，则他会重新分配您的方法genPartitionKey=(Dictionary<string, EntityProperty> props)=>{return props["RowKey"].ToString();}

与第二个相同

在这个表达中，他把这两种方法都称为var tableRecords =ReadCSV(lines, dataclass.TableSchema.Fields).Select(props => new DynamicTableEntity(genPartitionKey(props), genRowKey(props), string.Empty, props)).ToList();

我称之为

Validate(DependentMethod);