.Net判断数据库是否为空

[fox0897]

现有.net如下代码:
if()
{
double i;double j;string sum;
i = Double.Parse (txtSum .Text);
j = Double.Parse (txtMoney .Text );
sum = (i - j).ToString();
txtCinder .Text = sum.ToString ();
}
else
{
double x;double y;double z;double n;string sum;
x = Double .Parse (cmd.ExecuteScalar().ToString ());
y = Double .Parse (cmd1.ExecuteScalar ().ToString ());
z = Double .Parse (txtMoney .Text );
n = Double .Parse (cmd2.ExecuteScalar ().ToString ());
sum = ((x - y) - z + n).ToString();
txtCinder .Text = sum;
想在if()的括号里加个判断,判断数据库里是否有数据存在,没有则执行if块的语句,存在则执行else块的语句!谁能帮帮俺哈!

[xray2005]

用SqlDataAdapter就是了噻
然后,if(myReader.Read()) //如果有数据
{
...
}
else //如果没有数据
{
...
}

[fox0897]

没有用啊!还是无法判断,请大侠在给个更好的解决方法!!!!