点击查询就执行一个SQL语句，为啥有错？

[wincoman]

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnChaxun.Click
' Set the SelectCommand properties...
myDataAdapter.SelectCommand = New SqlCommand()
myDataAdapter.SelectCommand.Connection = myConnection
myDataAdapter.SelectCommand.CommandText = _
"SELECT au_lname, au_fname, title, price " & _
"FROM authors " & _
"JOIN titleauthor ON authors.au_id = titleauthor.au_id " & _
"JOIN titles ON titleauthor.title_id = titles.title_id " & _
"ORDER BY au_lname, au_fname"
myDataAdapter.SelectCommand.CommandType = CommandType.Text

' Open the database connection...
myConnection.Open()
' Now execute the command...
myDataAdapter.SelectCommand.ExecuteNonQuery()

' Fill the DataSet object with data...
myDataAdapter.Fill(myDataSet, "authors")

' Close the database connection...
myConnection.Close()

' Set the DataGrid properties to bind it to our data...
grdAuthorTitles.DataSource = myDataSet
grdAuthorTitles.DataMember = "authors"

' Declare objects for the DataGrid...
Dim objDataGridTableStyle As New DataGridTableStyle()
Dim objTextCol As New DataGridTextBoxColumn()

' Set the AlternatingBackColor property...
objDataGridTableStyle.AlternatingBackColor = Color.WhiteSmoke

' Set the MappingName for the DataGridTableStyle...
objDataGridTableStyle.MappingName = "authors"

' Set the MappingName for the first column...
objTextCol.MappingName = "au_lname"
' Set the new HeaderText...
objTextCol.HeaderText = "Last Name"
' Add the column to the DataGridTableStyle...
objDataGridTableStyle.GridColumnStyles.Add(objTextCol)

' Get a new reference to the DataGridTextBoxColumn...
objTextCol = New DataGridTextBoxColumn()
' Set the MappingName for the second column...
objTextCol.MappingName = "au_fname"
' Set the new HeaderText...
objTextCol.HeaderText = "First Name"
' Add the column to the DataGridTableStyle...
objDataGridTableStyle.GridColumnStyles.Add(objTextCol)

' Get a new reference to the DataGridTextBoxColumn...
objTextCol = New DataGridTextBoxColumn()
' Set the MappingName for the third column...
objTextCol.MappingName = "title"
' Set the new HeaderText...
objTextCol.HeaderText = "Book Title"
' Set the Width of the column...
objTextCol.Width = 304
' Add the column to the DataGridTableStyle...
objDataGridTableStyle.GridColumnStyles.Add(objTextCol)

' Get a new reference to the DataGridTextBoxColumn...
objTextCol = New DataGridTextBoxColumn()
' Set the MappingName for the fourth column...
objTextCol.MappingName = "price"
' Set the new HeaderText...
objTextCol.HeaderText = "Retail Price"
' Set the Alignment within the column...
objTextCol.Alignment = HorizontalAlignment.Right
' Add the column to the DataGridTableStyle...
objDataGridTableStyle.GridColumnStyles.Add(objTextCol)

' Add the DataGridTableStyle to the DataGrid...
grdAuthorTitles.TableStyles.Add(objDataGridTableStyle)

End Sub

[timmy3310]

出了什么错？
错误信息是什么

[zwztu]

请详细说明错误信息！

[wincoman]

在myConnection.Open()处，报"未处理的“System.Data.SqlClient.SqlException”类型的异常出现在 system.data.dll 中
其他信息：系统错误。

[heroyujun]

应该是
"SELECT authors.au_lname, authors.au_fname, authors.title,authors.price " & _
"FROM authors " & _
"JOIN titleauthor ON authors.au_id = titleauthor.au_id " & _
"JOIN titles ON titleauthor.title_id = titles.title_id " & _
"ORDER BY au_lname, au_fname"

[hilanderst]

先解决myConnection的问题，然后再说sql执行的问题；
先看看myConnection的设置。

[holydiablo]

是啊

看这些代码和在一堆棉絮里找针是一样的

[wincoman]

' Import Data and OleDb namespaces...
Imports System.Data
Imports System.Data.SqlClient
Public Class Form1
Inherits System.Windows.Forms.Form
' Declare objects...
Dim myConnection As SqlConnection = New SqlConnection("server= (wangf);database=pubs;uid=sa;pwd=963")
Dim myDataAdapter As New SqlDataAdapter()
Dim myDataSet As DataSet = New DataSet()