所以我尝试使用实体框架和c#创建一个注册方法,这是方法:
//Button create new account
private void BtnSignUp_Click(object sender, EventArgs e)
{
IEnumerable<DriverAcount> list = from a in context.DriverAcounts select a;
foreach (var Ac in list)
{
if (TxBoxNewUserName.Text != Ac.Login)
{
if (TxtBoxPASS1.Text == TxBoxPass.Text)
{
Ac.Login = TxBoxNewUserName.Text;
Ac.Password = TxtBoxPASS1.Text;
context.DriverAcounts.Add(Ac);
MessageBox.Show("the account is create succefuly");
TxBoxNewUserName.Text = "";
TxtBoxPASS1.Text = "";
TxBoxPass.Text = "";
break;
}
else
{
MessageBox.Show("the two passwords didn't matched");
}
TxBoxNewUserName.Text = "";
TxtBoxPASS1.Text = "";
TxBoxPass.Text = "";
continue;
}
else
{
MessageBox.Show("this username is already exist, please choose another one");
TxBoxNewUserName.Text = "";
TxtBoxPASS1.Text = "";
TxBoxPass.Text = "";
break;
}
}
context.SaveChanges();
}
问题是当我想要添加一个新用户时,它应该查看它是否存在于数据库中,但是它没有正确执行,例如,如果我们在DB name1中有两个名称和 name2 ,在TextBox中我们有 name2 ,即使它已经存在,它也会在数据库中添加 name2 。 所以如果有人有想法我会非常感激。
答案 0 :(得分:0)
您需要再次查看代码并准确理解它正在做什么 - 您是否已连接调试器并逐步完成它?如果检索到的第一个名称与文本框中的名称不匹配,则将始终在foreach
循环的第一次迭代中创建驱动程序名称。所有其他人都将被忽略。
您可以尝试这样做。当你只想检查一个记录是否存在时,不需要查询所有记录(就像你现在正在做的那样)。
private void BtnSignUp_Click(object sender, EventArgs e)
{
// This performs a case sensitive match on the login name, you'll need to change it if you want to ignore case
DriverAcount existingAccount = context.DriverAcounts.FirstOrDefault(d => d.Login == TxBoxNewUserName.Text);
if (existingAccount != null)
{
MessageBox.Show("This username already exists, please choose another one.");
}
else
{
if (TxtBoxPASS1.Text == TxBoxPass.Text)
{
Ac.Login = TxBoxNewUserName.Text;
Ac.Password = TxtBoxPASS1.Text;
context.DriverAcounts.Add(Ac);
// Only need to call this if you've made changes, so I've moved it here
context.SaveChanges();
MessageBox.Show("The account was created successfully");
}
else
{
MessageBox.Show("The two passwords didn't match each other.");
}
}
TxBoxNewUserName.Text = "";
TxtBoxPASS1.Text = "";
TxBoxPass.Text = "";
}