收费系统需要这样一个功能：首先用DataGridView浏览所有用户信息，然后可以删除指定行的用户信息，最后更新这一变化。界面如图：

1、首先检测要删除的用户是否是当前正在使用的用户：

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">'查看改用户是否正在被使用,若正在使用则不能删除
	If Trim(DGVuser.CurrentRow.Cells(0).Value) = frmLogin.txtUID.Text Then
	MsgBox("该用户正在使用，不能删除！","正在使用")
		Exit Sub
	End If</span>

2、然后在删除指定数据行：

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">          '删除datagridview中的数据行
  	'DGVuser.Rows.Remove(DGVuser.CurrentRow) 也可
	DGVuser.Rows.RemoveAt(DGVuser.CurrentRow.Index)</span>

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">Public Class dm_datatable
Private _dt As DataTable
	Public Property DT As DataTable
	Get
		Return _dt
	End Get
	Set(ByVal value As DataTable)
		_dt = value
	End Set
	End Property
End Class</span>

<span style="WHITE-SPACE: normal"><span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px"> </span></span>

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">Dim dt As New DataModel.dm_datatable
dt.DT = DGVuser.DataSource</span>

<span style="WHITE-SPACE: normal"><span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px"> </span></span>

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">'删除指定用户
Public Function deleteUser(ByVal dm_dt As DataModel.dm_datatable) As Boolean
Dim connString As String = _
"Persist Security Info=true;Data Source=192.168.24.158;Initial Catalog=CR_Charge_SYS;User ID=sa;PWD=123456"
Dim sqlconn As New sqlConnection(connString)
Dim sqltxt As String = "select * from User_info"
Dim sqlcmd As New sqlCommand(sqltxt,sqlconn)
Dim da As New sqlDataAdapter(sqlcmd)
Dim ds As New DataSet
Dim dt As New DataTable
da.UpdateCommand = sqlcmd
Dim mybuilder As New sqlCommandBuilder(da)
Try
	dt = dm_dt.DT.Copy
	ds.Tables.Add(dt)
	sqlconn.Open()
	da.Update(ds,"User_info")
	Return True
Catch ex As Exception
	MsgBox(ex.Message)
Return False
Finally
	sqlconn.Close()
	sqlcmd = Nothing
End Try
	Return Nothing
End Function</span>

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">'删除指定用户
Public Function deleteUser(ByVal dt As DataModel.dm_datatable) As Boolean
Dim sqlUserInfo As New ChargeSystemDAL.dal_User_info
	Return sqlUserInfo.deleteUser(dt)
End Function</span>

<span style="FONT-FAMILY: KaiTi_GB2312; FONT-SIZE: 18px">Dim dt As New DataModel.dm_datatable
'数据更改更新到数据库
If bllUserinfo.deleteUser(dt) = True Then
MsgBox("成功删除用户！","成功")
Exit Sub
Else
MsgBox("未能成功删除用户，详情请咨询管理员！","失败")
Exit Sub
End If</span>