Vb.net 从sql查询中获取单个值到文本框中
sql查询的结果是一个值,我想在标签中显示,但不知道如何显示。我有一个创建数据集的解决方案,将查询结果放入该数据集中,并按行(0)和列(0)获取数据,但我想有一种更聪明的方法Vb.net 从sql查询中获取单个值到文本框中,vb.net,dataset,streamreader,Vb.net,Dataset,Streamreader,sql查询的结果是一个值,我想在标签中显示,但不知道如何显示。我有一个创建数据集的解决方案,将查询结果放入该数据集中,并按行(0)和列(0)获取数据,但我想有一种更聪明的方法 Private myquery As String Sub New(ByVal query As String) myquery = query End Sub Public Sub query_Send() Dim myconn As New SqlConnection("Data Source=DB;
Private myquery As String
Sub New(ByVal query As String)
myquery = query
End Sub
Public Sub query_Send()
Dim myconn As New SqlConnection("Data Source=DB;Integrated Security=TRUE")
Dim mycmd As SqlCommand = New SqlCommand(Me.myQuery, myconn)
Dim myTable As New DataTable
Dim previousConnectionState As ConnectionState = myconn.State
Try
If myconn.State = ConnectionState.Closed Then
myconn.Open()
Dim myDA As New SqlDataAdapter(mycmd)
myDA.Fill(myTable)
tb.text = **...**
End If
If previousConnectionState = ConnectionState.Closed Then
myconn.Close()
End If
End Try
End Sub
你可以用
您可以将
值放入文本框中。ExecuteScalar返回结果集第一行的第一个值(相当于行(0)。列(0)
),当未返回任何记录时,值为无
请尝试以下内容:
Using myconn As New SqlConnection("Data Source=DB;Integrated Security=TRUE")
Dim myDA As New SqlDataAdapter()
myDA.SelectCommand = New SqlCommand(myQuery, myconn)
myDA.Fill(myTable)
Return myTable
End Using
或者,您可以使用
myTable.Rows(0).ItemArray(0).ToString()
适合我,感谢code Dim sql作为字符串Dim cmd作为新的OleDb.OleDbCommand con.Open()sql=“SELECT MAX(pos)FROM rac”cmd.Connection=con cmd.CommandText=sql Dim value As Object=cmd.ExecuteScalar me.TextBox6.Text=value+1
Using myconn As New SqlConnection("Data Source=DB;Integrated Security=TRUE")
Dim myDA As New SqlDataAdapter()
myDA.SelectCommand = New SqlCommand(myQuery, myconn)
myDA.Fill(myTable)
Return myTable
End Using