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我想檢查用戶名是否已經存在於數據庫中,如果是,錯誤信息會提示「用戶名已存在」。現在我有這個代碼,但它不工作。程序仍然接受用戶名,即使它是從數據庫中複製的。有人可以幫我出去嗎?這裏是我的整個註冊碼:當用戶註冊時,用戶名檢查不起作用-asp.net
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["RegistrationConnectionString"].ConnectionString);
conn.Open();
string checkuser = "select count(*) from UserData where Username = '" + txtUser.Text + "'";
SqlCommand scm = new SqlCommand(checkuser, conn);
int temp = Convert.ToInt32(scm.ExecuteScalar().ToString());
if (temp == 1) // check if user already exist.
{
Response.Write("User already existing");
}
conn.Close();
}
}
protected void btn_Registration_Click(object sender, EventArgs e)
{
try
{
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["RegistrationConnectionString"].ConnectionString);
conn.Open();
string insertQuery = "insert into UserData(Username,Firstname,Lastname,Email,Password,CustomerType,DeliveryAddress,Zip,ContactNumber)values(@Username,@Firstname,@Lastname,@Email,@Password,@CustomerType,@DeliveryAddress,@Zip,@ContactNumber)";
SqlCommand scm = new SqlCommand(insertQuery, conn);
scm.Parameters.AddWithValue("@Username", txtUser.Text);
scm.Parameters.AddWithValue("@Firstname", txtFN.Text);
scm.Parameters.AddWithValue("@Lastname", txtLN.Text);
scm.Parameters.AddWithValue("@Email", txtEmail.Text);
scm.Parameters.AddWithValue("@Password", BusinessLayer.ShoppingCart.CreateSHAHash(txtPW.Text));
scm.Parameters.AddWithValue("@CustomerType", RadioButtonList1.SelectedItem.ToString());
scm.Parameters.AddWithValue("@DeliveryAddress", txtAddress.Text);
scm.Parameters.AddWithValue("@Zip", txtZip.Text);
scm.Parameters.AddWithValue("@ContactNumber", txtContact.Text);
scm.ExecuteNonQuery();
Session["Contact"]= txtContact.Text;
Session["Email"] = txtEmail.Text;
Session["DeliveryAddress"] = txtAddress.Text;
label_register_success.Text = ("Registration Successful!");
//Response.Redirect("Home.aspx");
conn.Close();
}
catch (Exception ex)
{
Response.Write("Error:" + ex.ToString());
}
}
香港專業教育學院嘗試過,但還是接受了相同的用戶名@Heinz Siahaan –
你嘗試像上面我編輯的代碼?如果'(temp == 1)'改變爲'if(temp> 0)',我會改變你插入用戶的概率。 –
。先生。它不讀取其他部分中的第二個「scm」。它說它已經被用作父範圍來表示別的東西。 @ Heinz Siahaan –