日期:2014-05-17 浏览次数:20572 次
N年前我们是这样来 拼接查询字符串的:
[c-sharp] view plaincopy
public string Test(string a, string b, string c,string d)
{
string sql = "SELECT * FROM Users WHERE 1=1";
if (!string.IsNullOrEmpty(a))
{
sql += " AND name='" + a + "'";
}
if (!string.IsNullOrEmpty(b))
{
sql += " AND age='" + b+ "'";
}
if (!string.IsNullOrEmpty(c))
{
sql += " AND sex='" + c + "'";
}
if (!string.IsNullOrEmpty(d))
{
sql += " AND address='" + d + "'";
}
return sql.ToString();
}
现在我们使用linq来实现上边的代码:
[c-sharp] view plaincopy
public void Test(string a, string b, string c,string d)
{
QueryContext query = new QueryContext();
var q = from u in query.Users
select u;
if (!string.IsNullOrEmpty(a))
{
q = q.Where(p => p.name == a);
}
if (!string.IsNullOrEmpty(b))
{
q = q.Where(p