急啊！！！！！HELP

我做了个投票模块可是输入主题时第一次点添加主题时成功了第二次哪怕里面是空的再点都会加入前一个添加的主题，反正都会出现两次

哪位高手帮帮我啊：

我写的类：
public class TitleControl
{
public TitleControl()
{
//
// TODO: 在此处添加构造函数逻辑
//

}
public int AddTitle(string TitleName)
{
string set;
string mysql;
int row1;
SqlConnection mycon;
SqlCommand mycmd;

set = Convert.ToString(ConfigurationManager.ConnectionStrings["con"].ToString());
mysql = "insert into VoteTitle(TitleName)";
mysql = mysql + "values('" + TitleName + "')";
mycon = new SqlConnection(set);
mycon.Open();
mycmd = new SqlCommand(mysql,mycon);

row1=mycmd.ExecuteNonQuery();
return row1;

}
public SqlDataReader bind()
{
string set;
string mysql;
SqlConnection mycon;
SqlCommand mycmd;
SqlDataReader mydr;

set = Convert.ToString(ConfigurationManager.ConnectionStrings["con"].ToString());
mysql = "select * from VoteTitle";
mycon = new SqlConnection(set);
mycon.Open();
mycmd = new SqlCommand(mysql, mycon);
mydr = mycmd.ExecuteReader();
return mydr;
}
}

页面：

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
/* TitleControl Title = new TitleControl();
SqlDataReader mydr1;
mydr1 = Title.bind();

GridView1.DataSource = "mydr1";
GridView1.DataBind();*/
TitleControl mytc = new TitleControl();
SqlDataReader mydr;
mydr = mytc.bind();
GridView1.DataSource = mydr;
GridView1.DataBind();

}
protected void Button1_Click(object sender, EventArgs e)
{
int row;
TitleControl Title = new TitleControl();
row=Title.AddTitle(TextBox1.Text);
if(row!=0)
Label1.Text = "添加成功";
}
}