方法一:拼凑完整SQL(不推荐)
比如:string sql = "select * from aaa where id=" + TextBox1.Text;方法二:用参数
比如:string sql = "select * from aaa where id=@id";然后在SqlCommand对象(或其他类型的Command)里, cmd.Parameters.AddWithValue("@id",TextBox1.Text);
比如:string sql = "select * from aaa where id=" + TextBox1.Text;方法二:用参数
比如:string sql = "select * from aaa where id=@id";然后在SqlCommand对象(或其他类型的Command)里, cmd.Parameters.AddWithValue("@id",TextBox1.Text);
{
sql += " and uname='"+ TextBox1.Text.Trim() +"'";
}if(TextBox2.Text.Trim() != string.Empty)
{
sql += " and email='"+ TextBox2.Text.Trim() +"'";
}
string b = textBox2.Text.Trim();
SqlCommand sc = mycon.CreateCommand();
sc.CommandText = "select uid from test where uid=@uid";
sc.Parameters.AddWithValue("@uid", textBox1.Text.Trim());
SqlDataReader sd = sc.ExecuteReader();
string c=sd.Read().ToString().Trim();
textBox2.Text = sd.Read().ToString().Trim();
if (a.Equals(c))
{
MessageBox.Show("帐号存在");
}
else
{
MessageBox.Show("帐号不存在!请重新输入!" + sd.Read().ToString().Trim(), "提示");
textBox1.Clear();
textBox1.Focus();
sd.Close();
}
怎么取出的结果是bool值啊?
string a = textBox1.Text.Trim();
string b = textBox2.Text.Trim();
SqlCommand sc = mycon.CreateCommand();
sc.CommandText = "select uid from test where uid=@uid";
sc.Parameters.AddWithValue("@uid", textBox1.Text.Trim());
SqlDataReader sd = sc.ExecuteReader();
string c=sd.Read().ToString().Trim();
textBox2.Text = sd.Read().ToString().Trim();
if (a.Equals(c))
{
MessageBox.Show("帐号存在");
}
else
{
MessageBox.Show("帐号不存在!请重新输入!" + sd.Read().ToString().Trim(), "提示");
textBox1.Clear();
textBox1.Focus();
sd.Close();
}
怎么取出的结果是bool值啊?=======================================
定义个bool变量(函数也是bool)
if boo=true
else boo=false
証明你數據庫里有這個值了呀
我进行判断时 他提示无法转为BOOL 郁闷