Question

vb.net datagridview数据修改同步到数据库

Textbox1输入查询命令（select语句后查询结果在datagridview中显示，在datagridview中修改数据按保存按钮数据更新到数据库）
查询没有错误，但修改数据后保存出现错误 ，错误行在下面代码红色标出了，错误提示未将对象引用设置到对象的实例，我查询的表设置了主键
Imports System.Data.SqlClient
Public Class Form1

Dim con As New SqlConnection
Dim Com As SqlCommand
Dim da As SqlDataAdapter
Dim ds As DataSet

'查询按钮代码
Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
con = New SqlConnection("data source=mypc;initial catalog=xiaoshouxt;" & "integrated security=false;user=sa;password=8348538620")
con.Open()
Com = New SqlCommand(TextBox1.Text, con)
Dim da As SqlDataAdapter
Dim ds As DataSet

da = New SqlDataAdapter(com)
ds = New DataSet
da.Fill(ds, "ch")
DataGridView1.DataSource = ds.Tables("ch")
End Sub

'修改datagridview1中数据保存按钮
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
con = New SqlConnection("data source=mypc;initial catalog=xiaoshouxt;" & "integrated security=false;user=sa;password=8348538620")
con.Open()
'保存表身修改后的数据
Dim A As New SqlCommandBuilder(da)

da.Update(ds, "ch")
con.close()
End Sub
End Class
更多 0

Answer 1

变量的作用域的概念错误：
改用下面代码：

Imports System.Data.SqlClient
Public Class Form1

Dim con As New SqlConnection
Dim Com As SqlCommand
Dim da As SqlDataAdapter
Dim ds As DataSet

'查询按钮代码
Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
con = New SqlConnection("data source=mypc;initial catalog=xiaoshouxt;" & "integrated security=false;user=sa;password=8348538620")
con.Open()
Com = New SqlCommand(TextBox1.Text, con)
'Dim da As SqlDataAdapter '这行不要
'Dim ds As DataSet '这行不要

da = New SqlDataAdapter(com)
ds = New DataSet
da.Fill(ds, "ch")
DataGridView1.DataSource = ds.Tables("ch")
End Sub

'修改datagridview1中数据保存按钮
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
'下面两行也不要
'con = New SqlConnection("data source=mypc;initial catalog=xiaoshouxt;" & "integrated security=false;user=sa;password=8348538620")
'con.Open()

'保存表身修改后的数据
Dim A As New SqlCommandBuilder(da)
da.Update(ds, "ch")
con.close()
End Sub
End Class