rd = cmd.ExecuteReader

来源：百度知道 编辑：UC知道 时间：2024/07/08 10:33:29
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim conn As New SqlConnection()
conn.ConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database.mdf;Integrated Security=True;User Instance=True"
Dim cmd As New SqlCommand("select * from user", conn)
conn.Open()
Dim rd As SqlDataReader
rd = cmd.ExecuteReader
rd.Read()
Label1.Text = rd.GetDataTypeName(1).ToString
conn.Close()
End Sub
-----------------------------------------------------------------
Dim da As SqlDataAdapter = New SqlDataAdapter("select * from usrT", conn)
Dim ds As DataSet = New DataSet
da.Fill(ds, "usrT")
Dim dr As DataRow = ds.Tables("usrT").NewRow
dr("usr") = "sht003"

user是sql的保留关键字

Dim cmd As New SqlCommand("select * from [user]", conn)这样即可

user是sql的保留关键字，把表名换了
while(rd.read())
{
Label1.Text = rd.Item(0)
Label2.Text = rd.Item(1)
}
rd.close();

修改的话你最好加个自增长字段，要不就把usr设为主键
//修改
sqlcommend sqlcom=new sqlcommand("update usrT set psw=@psw where usr=@usr", conn);
sqlparameter sp=new sqlparameter("@psw","123");
sqlcom.parameters.add(sp);
sp=new sqlparameter("@usr","username");
sqlcom.parameters.add(sp);
conn.open();
sqlcommend.executenonquery();
conn.close();
//新增
sqlcommend sqlcom=new sqlcommand("insert into usrT(usr,psw) values(@usr,@psw)", conn);
sqlparameter sp=new sqlparameter("@psw","123");
sqlcom.parameters.add(sp);
sp=new sqlparameter("@usr","username");
sqlcom.parameters.add(sp);
conn.open();
sq