问题描述
我试图执行一个存储过程,然后使用if语句来检查空值,我的短来了。我是一个VB的家伙,所以请与我裸露,如果我做一个小学生语法错误。
I'm trying to execute a stored procedure and then use an if statement to check for null values and I'm coming up short. I'm a VB guy so please bare with me if I'm making a schoolboy syntax error.
objConn = new SqlConnection(strConnection);
objConn.Open();
objCmd = new SqlCommand(strSQL, objConn);
rsData = objCmd.ExecuteReader();
rsData.Read();
if (!(rsData["usr.ursrdaystime"].Equals(System.DBNull.Value)))
{
strLevel = rsData["usr.ursrdaystime"].ToString();
}
这是否让我检查SQL连接是否返回只是一个值,这样的话我的填充字符串?
Would this allow me to check whether the SQL connection is returning just a value and if so then populating my string?
我如果正在返回我曾经能够只是检查下面看到一个值,不知道我M用C#做正确
I'm used to being able to just check the below to see if a value is being returned and not sure I'm doing it correctly with C#
如果不IsDBNull以便(rsData(usr.ursrdaystime))
If Not IsDBNull(rsData("usr.ursrdaystime"))
任何帮助,将不胜感激!
Any help would be appreciated!
推荐答案
这应该工作。
if (rsData["usr.ursrdaystime"] != System.DBNull.Value))
{
strLevel = rsData["usr.ursrdaystime"].ToString();
}
还需要使用语句添加,如波纹管:
also need to add using statement, like bellow:
using (var objConn = new SqlConnection(strConnection))
{
objConn.Open();
using (var objCmd = new SqlCommand(strSQL, objConn))
{
using (var rsData = objCmd.ExecuteReader())
{
while (rsData.Read())
{
if (rsData["usr.ursrdaystime"] != System.DBNull.Value)
{
strLevel = rsData["usr.ursrdaystime"].ToString();
}
}
}
}
}
这会全自动处理块{..}之外(关闭)的资源。
this'll automaticly dispose (close) resources outside of block { .. }.
这篇关于如果DBNull的声明的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!