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C# 处理空结果_C#_Asp.net_Asp.net Mvc_Database_Linq To Sql - Fatal编程技术网

C# 处理空结果

C# 处理空结果,c#,asp.net,asp.net-mvc,database,linq-to-sql,C#,Asp.net,Asp.net Mvc,Database,Linq To Sql,我有一个db请求,它可能返回null: Pony MyPony = db.Pony.Where(p => p.PonyOwnerId == user.UserId).First(); 如果my db中没有行,则会显示一条错误消息 如何接受空查询?您可以编写: Pony myPony = db.Pony.Where(p => p.PonyOwnerId == user.UserId).FirstOrDefault(); if( myPony != null ) { // Do

我有一个db请求,它可能返回
null

Pony MyPony = db.Pony.Where(p => p.PonyOwnerId == user.UserId).First();
如果my db中没有行,则会显示一条错误消息

如何接受空查询?

您可以编写:

Pony myPony = db.Pony.Where(p => p.PonyOwnerId == user.UserId).FirstOrDefault();
if( myPony != null ) {
    // Do something
}
你可以写:

Pony myPony = db.Pony.Where(p => p.PonyOwnerId == user.UserId).FirstOrDefault();
if( myPony != null ) {
    // Do something
}
你可以用

你可以用

var MyPony = db.Pony.FirstOrDefault(p => p.PonyOwnerId != null && p.PonyOwnerId == user.UserId);
var MyPony = db.Pony.Where(p => p.PonyOwnerId != null && p.PonyOwnerId == user.UserId).FirstOrDefault();
if (db.Pony.FirstOrDefault(p => p.PonyOwnerId != null && p.PonyOwnerId == user.UserId) != null)
{
 //Do stuff
}