如何解决最好的重载方法匹配有一些无效的参数数据集 [英] How to solve the best overloaded method match for has some invalid arguments dataset

问题描述

我使用数据集并且我正确地做了所有事情，字段作为数据库字段



但是这个消息总是出现给我：



编译错误



描述：编译服务此请求所需的资源时出错。请查看以下特定错误详细信息并相应地修改源代码。



编译器错误消息：CS1502：'KutubDataSetTableAdapters.BooksTableAdapter.InsertBook（字符串，字符串，十进制？，int？，int？，ref int）的最佳重载方法匹配？）'有一些无效的论点

I work with data set and I did every thing correctly, the fields as the Database fields

but always this message appears to me:

Compilation Error

Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.

Compiler Error Message: CS1502: The best overloaded method match for 'KutubDataSetTableAdapters.BooksTableAdapter.InsertBook(string, string, decimal?, int?, int?, ref int?)' has some invalid arguments

 int InsertBook(string BookName, string Description, int Price, int Publisher, int Category, int PublishDate)
    {

        KutubDataSetTableAdapters.BooksTableAdapter Bta = new KutubDataSetTableAdapters.BooksTableAdapter();

        return Bta.InsertBook(BookName, Description, Price, Publisher, Category, PublishDate);}
}

我试图用这个：

I tried to use this:

int InsertBook(string BookName, string Description, decumal? Price, int? Publisher, int? Category,ref int? PublishDate)

它没有成功..

And it didn't success..

推荐答案

在传入参数时需要指定 ref 修饰符，但不要重新声明参数类型。



此外，参数传递为 ref 或 out 必须完全匹配声明的类型。你不能将 ref int 传递给 ref int？参数，所以你需要使用临时的本地变量。



试试这个：

You need to specify the ref modifier when you pass the parameter in, but you don't re-state the argument types.

Also, arguments passed as ref or out must match the declared type exactly. You can't pass a ref int to a ref int? parameter, so you'll to use need a temporary local variable.

Try this:

int? thePublishDate = PublishDate;
return Bta.InsertBook(BookName, Description, Price, Publisher, Category, ref thePublishDate);

查看您的外部过程中的变量Price是否正在传递一个int数据类型，但您的另一个方法是期望可以为空的十进制小数？你不能为一个可空的内容交换一个int。



同样的逻辑适用于你的其他几个参数，特别是int和int？。这些数据类型不同。



http://stackoverflow.com/questions/6389437/explanation-of-int-vs-int [ ^ ]

Look at your variable Price in your outer procedure you are passing an int datatype but your other method is expecting a nullable decimal, decimal?. You cannot interchange an int for a nullable.

And the same logic applies to several of your other parameters, specifically the int and the int?. These are not the same data type.

http://stackoverflow.com/questions/6389437/explanation-of-int-vs-int[^]

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