如何检查用户是否已经存在于数据库中
问题描述:
我有一个表格我只是想检查用户是否已经存在或没有,如果没有,那么它保存在数据库中否则显示错误信息用户已经存在知道这个问题我问了很多次,但我没有找到我的解决方案 这里是我的aspx代码:如何检查用户是否已经存在于数据库中
protected void btnSubmit_Click(object sender, EventArgs e)
{
con.Open();
string FirstName = tbFirstName.Text;
string LastName = tbLastName.Text;
string Email = tbEmail.Text;
string Pass = tbPass.Text;
string ConfirmPass = tbConfirmPass.Text;
using (SqlCommand cmd = con.CreateCommand())
{
cmd.CommandText = "Insert into UserDetails(@FirstName,@LastName,@Email,@Pass,@ConfirmPass)values('" + tbFirstName.Text + "','" + tbLastName.Text + "','" + tbEmail.Text + "','" + tbPass.Text + "','" + tbConfirmPass.Text + "')";
cmd.Parameters.AddWithValue("@FirstName", tbFirstName.Text.Trim());
cmd.Parameters.AddWithValue("@LastName", tbLastName.Text.Trim());
cmd.Parameters.AddWithValue("@Email", tbEmail.Text.Trim());
cmd.Parameters.AddWithValue("@Pass", tbPass.Text.Trim());
cmd.Parameters.AddWithValue("@ConfirmPass", tbConfirmPass.Text.Trim());
}
con.Close();
tbFirstName.Text = "";
tbLastName.Text = "";
tbEmail.Text = "";
tbPass.Text = "";
tbConfirmPass.Text = "";
tbFirstName.Focus();
}
在此
上只能创建按钮,用户点击事件,但我想,以验证它是否存在于数据库中或不是
答
试试这个代码,它可能会帮助你。在您的点击事件中调用此函数。
public void CheckUser()
{
string strconn = @"Data Source=appserver3;Initial Catalog=Bart;User ID=bart1;[email protected]";
SqlDataReader reader = null;
SqlConnection conn = null;
conn = new SqlConnection(strconn);
conn.Open();
DateTime Dt_Time = DateTime.Now;
string FirstName = tbFirstName.Text;
SqlCommand cmd = new SqlCommand("select FirstName from UserDetails where @FirstName='" + tbFirstName.Text + "'", conn);
cmd.Parameters.AddWithValue("@FirstName", tbFirstName.Text.Trim());
reader = cmd.ExecuteReader();
if (reader != null && reader.HasRows)
{
Response.Write("<script>alert('User Already Exist');</script>");
}
else
{
string strquery = string.Format("insert into UserDetails values('{0}')", @FirstName);
cmd = new SqlCommand(strquery, conn);
int count = (int)cmd.ExecuteNonQuery();
Response.Write("FirstName:" + FirstName);
}
}
+0
感谢您的代码工作 – amitesh 2013-04-29 15:22:11
必须有至少100个这个问题的重复。 – 2013-04-29 14:49:23
@Aaron你可以给我发几条这样的排队的链接吗 – amitesh 2013-04-29 14:50:40
这个搜索有697个结果 - 他们并不都是相关的,但我确定很多在这个第一页上。 http://*.com/search?q=insert+already+exists+sql-server – 2013-04-29 14:51:22