如何解决；在上下文中指定的布尔型表达式，其中条件在“number”附近被排除；vb.net中的错误 导入系统数据 导入System.Data.SqlClient 公开课表格2 私有子按钮1\u单击（ByVal sender作为System.Object，ByVal e作为System.EventArgs）处理按钮1。单击 Dim cmd作为SqlCommand Dim conn As SqlConnection Dim dr2作为SqlDataReader Dim sql=“选择房间号、日期、ddate FROM date WHERE room number='”&nametxt.Text&“和date>='”&DateTimePicker1.Text&“和ddate

当您有一个名称中带有空格的字段时，应将其括在方括号中

Imports System.Data
Imports System.Data.SqlClient


Public Class Form2
    Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim cmd As SqlCommand
        Dim conn As SqlConnection
        Dim dr2 As SqlDataReader

        Dim sql = "SELECT room number,date,ddate FROM date WHERE room number = '" & nametxt.Text & "' AND date >= '" & DateTimePicker1.Text & "'AND ddate <= '" & DateTimePicker1.Text & "'OR Room number = '" & nametxt.Text & "'AND date = '" & DateTi    mePicker1.Text & "' "
        conn = New SqlConnection("Data Source=zahid\sqlexpress;Initial Catalog=test;Integrated Security=True")
        conn.Open()

        cmd = New SqlCommand(sql, conn)


        Try
            dr2 = cmd.ExecuteReader
            If dr2.Read = True Then
                MessageBox.Show("room not available...")
            Else
                MessageBox.Show("Login Successful...")
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

        If conn.State <> ConnectionState.Closed Then
            conn.Close()
        End If

    End Sub
End Class

Dim sql=“选择[房间号、日期、日期，其中[房间号]=”和_
“'”&nametxt.Text&“和日期>=”&DateTimePicker1.Text&”_
“'AND ddate=@dt AND ddate=@dt AND ddate如果字段的名称中有空格，则应将其括在方括号中

Imports System.Data
Imports System.Data.SqlClient


Public Class Form2
    Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim cmd As SqlCommand
        Dim conn As SqlConnection
        Dim dr2 As SqlDataReader

        Dim sql = "SELECT room number,date,ddate FROM date WHERE room number = '" & nametxt.Text & "' AND date >= '" & DateTimePicker1.Text & "'AND ddate <= '" & DateTimePicker1.Text & "'OR Room number = '" & nametxt.Text & "'AND date = '" & DateTi    mePicker1.Text & "' "
        conn = New SqlConnection("Data Source=zahid\sqlexpress;Initial Catalog=test;Integrated Security=True")
        conn.Open()

        cmd = New SqlCommand(sql, conn)


        Try
            dr2 = cmd.ExecuteReader
            If dr2.Read = True Then
                MessageBox.Show("room not available...")
            Else
                MessageBox.Show("Login Successful...")
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

        If conn.State <> ConnectionState.Closed Then
            conn.Close()
        End If

    End Sub
End Class

Dim sql=“选择[房间号、日期、日期，其中[房间号]=”和_
“'”&nametxt.Text&“和日期>=”&DateTimePicker1.Text&”_
“'和ddate=@dt和ddate=@dt和ddate
Dim sql = "SELECT [room number],date,ddate FROM date WHERE " & _
          "([room number] = @rnum  AND date >= @dt AND ddate <= @dt) " & _
          " OR ([Room number] = @rnum AND date = @dt)"

Dim sql = "SELECT [room number],date,ddate FROM date WHERE " & _
          "[room number] = @rnum  AND date >= @dt AND ddate <= @dt " 

Using conn = New SqlConnection("Data Source=zahid\sqlexpress;Initial Catalog=test;Integrated Security=True")
Using cmd = New SqlCommand(sql, conn)
    conn.Open()
    cmd.Parameters.AddWithValue("@rnum", nametxt.Text)
    cmd.Parameters.AddWithValue("@dt", DateTimePicker1.Value)
    Try
        Using dr2 = cmd.ExecuteReader
            ' Probably this test is wrong....
            If dr2.Read = True Then
                MessageBox.Show("room not available...")
            Else
                MessageBox.Show("Login Successful...")
            End If
        End Using
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Using
End Using
If conn.State <> ConnectionState.Closed Then
    conn.Close()
End If