如何解决C#SqlDataAdapter必须声明标量变量Sql Exception
C#的新手,并且在Windows窗体应用程序上工作。我试图对sql数据库执行更新查询,但始终遇到“必须声明标量变量”错误,我不明白为什么。
以下代码成功打开了连接。我的更新声明有效。浏览有关该主题的很多文章,但我只是没有看到我的错误...任何帮助将不胜感激。
public void SetJobStatus(long JobId)
{
string strsql = "update Jobmaster set jobstatus = 5 where equid = @stationId AND ID <> @jobId AND OfflineEntry = 0;";
using (sqlConnection conn = new sqlConnection())
{
conn.ConnectionString = GlobalVars.connString;
conn.open();
// use the connection here,and check to confirm it is open
if (conn.State != ConnectionState.Open)
{
if (conn != null)
{
conn.Close();
}
conn.open();
}
sqlCommand command;
sqlDataAdapter adapter = new sqlDataAdapter();
command = new sqlCommand(strsql,conn);
//below AddWithValue gives error:
//System.Data.sqlClient.sqlException: 'Must declare the scalar variable "@stationId".'
//command.Parameters.AddWithValue("@stationId",1);
//command.Parameters.AddWithValue("@jobId",JobId);
//next I tried this,and the same error:
//System.Data.sqlClient.sqlException: 'Must declare the scalar variable "@stationId".'
command.Parameters.Add("@stationId",sqlDbType.Int);
command.Parameters["@stationId"].Value = 1;
command.Parameters.Add("@jobId",sqlDbType.Int);
command.Parameters["@jobId"].Value = JobId;
adapter.UpdateCommand = new sqlCommand(strsql,conn);
adapter.UpdateCommand.ExecuteNonQuery();
}
}
解决方法
我已经检查了您的代码,需要进行一些更改。请尝试运行以下代码:
public void SetJobStatus(int JobId)
{
string strSql = "update Jobmaster set jobstatus = 5 where equid = @stationId AND ID <> @jobId AND OfflineEntry = 0;";
using (SqlConnection conn = new SqlConnection())
{
try
{
conn.ConnectionString = GlobalVars.connString;
conn.Open();
SqlCommand command = new SqlCommand(strSql,conn);
command.CommandType = CommandType.Text;
command.Parameters.Add("@stationId",SqlDbType.Int);
command.Parameters["@stationId"].Value = 1;
command.Parameters.Add("@jobId",SqlDbType.Int);
command.Parameters["@jobId"].Value = JobId;
command.ExecuteNonQuery();
}
catch (Exception ex)
{
if (conn.State == ConnectionState.Open)
{
conn.Close();
}
}
finally
{
if (conn.State == ConnectionState.Open)
{
conn.Close();
}
}
}
}
提示:
- 在任务完成后或出现错误时始终关闭连接。
感谢在这里发消息的每个人。 WSC的评论确实改变了技巧adapter.UpdateCommand = command;
。在进行WSC更改后,我尝试了三种添加参数的方法-其中两种有效,一种没有。
我的修订代码如下。我在代码中列出了所有三种变体,希望这对其他人有帮助。
public void SetJobStatus(long JobId)
{
string strSql = "update Jobmaster set jobstatus = 5 where equid = @stationId AND ID <> @jobId AND OfflineEntry = 0;";
using (SqlConnection conn = new SqlConnection())
{
conn.ConnectionString = GlobalVars.connString;
conn.Open();
// use the connection here,and check to confirm it is open
if (conn.State != ConnectionState.Open)
{
if (conn != null)
{
conn.Close();
}
conn.Open();
}
SqlCommand command;
SqlDataAdapter adapter = new SqlDataAdapter();
command = new SqlCommand(strSql,conn);
//works
command.Parameters.AddWithValue("@stationId",GlobalVars.stationId);
command.Parameters.AddWithValue("@jobId",JobId);
//works
//command.Parameters.Add("@stationId",SqlDbType.Int);
//command.Parameters["@stationId"].Value = 5;
//command.Parameters.Add("@jobId",SqlDbType.Int);
//command.Parameters["@jobId"].Value = JobId;
//throws error at adapter.UpdateCommand.ExecuteNonQuery line:
//'The parameterized query '(@stationId int,@jobId int)update Jobmaster set jobstatus = 5 wh' expects the parameter '@stationId',which was not supplied.'
//command.Parameters.Add("@stationId",SqlDbType.Int,5);
//command.Parameters.Add("@jobId",(int)JobId);
adapter.UpdateCommand = command;
adapter.UpdateCommand.ExecuteNonQuery();
}
}
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。