1
我在嘗試檢查輸入的用戶名是否已存在於數據庫中。但以上錯誤上升。執行命令時遇到致命錯誤
protected void txtUsername_TextChanged(object sender, EventArgs e)
{
MySqlConnection con = new MySqlConnection(con1);
try{
if (!string.IsNullOrEmpty(txtUsername.Text))
{
con.Open();
MySqlCommand cmd = new MySqlCommand("select username from client_login where [email protected]", con);
DataSet ds = new DataSet();
MySqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
checkusername.Visible = true;
imgstatus.ImageUrl = "NotAvailable.jpg";
lblStatus.Text = "UserName Already Taken";
}
else
{
checkusername.Visible = true;
imgstatus.ImageUrl = "Icon_Available.gif";
lblStatus.Text = "UserName Available";
}
}
else
{
checkusername.Visible = false;
}
con.Close();
}
catch(Exception ex){
Response.Write(ex);
}
}
和文本框代碼如下
` <asp:TextBox ID="txtUsername" runat="server" AutoPostBack="true" OnTextChanged="txtUsername_TextChanged"></asp:TextBox>`
誤差在執行Reader作爲 基地= {「命令執行過程中遇到致命錯誤。」}
添加堆棧跟蹤。 – Guy
stackTrace不生產 –