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找出SQLCommand查询中是否有行

sql asp.net

0

Jamie Taylor · 技术社区 · 15 年前

Dim conn As SqlConnection = New SqlConnection("server='h'; user id='w'; password='w'; database='w'; pooling='false'") 

conn.Open() 

Dim query As New SqlCommand("DECLARE @investor varchar(10), @sql varchar(1000) Select @investor = 69836 select @sql = 'SELECT * FROM OPENQUERY(db,''SELECT * FROM table WHERE investor = ''''' + @investor + ''''''')' EXEC(@sql)", conn) 

dgBookings.DataSource = query.ExecuteReader 
dgBookings.DataBind()

我需要添加一个 If 语句基本上表示 query 不返回行,然后显示特定标签

能做到吗?

2 回复 | 直到 15 年前

1

2

AdaTheDev 15 年前

尝试:

Dim conn As SqlConnection = New SqlConnection("server='h'; user id='w'; password='w'; database='w'; pooling='false'") 

conn.Open() 

Dim query As New SqlCommand("DECLARE @investor varchar(10), @sql varchar(1000) Select @investor = 69836 select @sql = 'SELECT * FROM OPENQUERY(db,''SELECT * FROM table WHERE investor = ''''' + @investor + ''''''')' EXEC(@sql)", conn) 

Dim rdr as SqlDataReader
rdr = query.ExecuteReader()

if (rdr.HasRows) then
   dgBookings.DataSource = rdr
   dgBookings.DataBind() 
else
    .....
end if

很明显,您可以确保对象被清理/处理,所以这只是为了演示 HasRows

2

Brandon Montgomery 15 年前

你将被退回 SqlDataReader ExecuteReader() ,而且 数据阅读器 有一个 HasRows

Dim oDR As SqlDataReader = query.ExecuteReader()

If oDR.HasRows Then
  lblNoRows.Visible = False
Else
  lblNoRows.Visible = True
End IF