error in retreiving data

See more:

C#

ASP.NET

C#4.0

how to retrive data

i created one table customer with email_id nvarchar(50) as p.k,cust_name nvarchar(50),cust_address nvarchar(50)

now in form i want to retrive customer name depending upon email address

i performed following:

here textbox1 is email id entered by user

protected void Button1_Click(object sender, EventArgs e)
  {
      string s = TextBox1.Text;
      objcus.name(s);
  }

public void name(string emailid)
      {
          int add = s.DMLQuery("select Customer_Name from Tbl_Customer where Email_Id =" + emailid);
      }

public int DMLQuery(string SqlCommandText)
       {

           Sqlconn = new SqlConnection(StrSqlconnection);
           Sqlconn.Open();
           sqlcmd = new SqlCommand();
           sqlcmd.CommandText = SqlCommandText;
           sqlcmd.Connection = Sqlconn;
           int i = sqlcmd.ExecuteNonQuery();
           return i;
       }

i am getting error on int i = sqlcmd.ExecuteNonQuery(); as " The multi-part identifier "shivani@ossagho.com" could not be bound."

pls teell what i missed

regards