将 SQL 数据读取器数据加载到 DataTable 时遇到问题
string query = "select * from cfo_daily_trans_hist";
try
{
using (SqlConnection connection = new SqlConnection(
cnnString))
{
SqlCommand command = new SqlCommand(query);
command.Connection = connection;
connection.Open();
var result = command.ExecuteReader();
DataTable datatable = new DataTable();
datatable.Load(result);
connection.Close();
}
}
因此，var result是通过ExecuteReader();创建的，并且HasRows是true，并且它显示了正确的结果字段数量。但是，我从中创建的 DataTable 是空的。
我做错了什么？我 99% 确定它正在获取数据，但我不知道如何通过 SqlDataReader 对象找到它来确定。
谢谢。
string query = "select * from cfo_daily_trans_hist";
try
{
using (SqlConnection connection = new SqlConnection(
cnnString))
{
SqlCommand command = new SqlCommand(query);
command.Connection = connection;
connection.Open();
var result = command.ExecuteReader();
DataTable datatable = new DataTable();
datatable.Load(result);
connection.Close();
}
}
So the var result is created through the ExecuteReader(); and HasRows is true, and it shows the correct amount of fields. However, the DataTable that I create from it is empty.
What am I doing wrong? I'm 99% sure it's getting data, but I don't know how to find it through the SqlDataReader object to make sure.
Thanks.
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使用
SqlDataAdapter而不是SqlDataReader。使用
SqlDataAdapter，您无需显式调用SqlConnection.Open()和SqlConnection.Close()。它在Fill()方法中处理。Instead of a
SqlDataReader, use aSqlDataAdapter.With a
SqlDataAdapter, you don't need to explicitly callSqlConnection.Open()andSqlConnection.Close(). It is handled in theFill()method.您可以尝试在sql命令语句中添加“COALESCE”...如果查询结果中有一些NULL值，则数据表将会出现问题
You can try to add "COALESCE" in your sql command statement ... if you have some NULL value in your query result, you will have problem with dataTable