论坛小问题。。。急!!
int UserID = "select from UserMessage where UserID =" + Convert.ToInt32(e.CommandArgument.ToString())+ "";运行时错误:
// 无法将类型“string”隐式转换为“int” // --------------------编程问答-------------------- 后面是字符串
前面是 int
当然不能这样赋值了 --------------------编程问答-------------------- 构造的查询是个串,不能赋给int --------------------编程问答--------------------
--------------------编程问答--------------------
string UserID = "select from UserMessage where UserID =" + Convert.ToInt32(e.CommandArgument.ToString())+ "";
int Userid = Convert.ToInt32(UserID );
Int UserID = Convert.ToInt32(String UID= "select from UserMessage where UserID =" + e.CommandArgument.ToString()+ "");
--------------------编程问答-------------------- 写错了。写错了。 --------------------编程问答--------------------
--------------------编程问答-------------------- 呵呵 --------------------编程问答-------------------- 加油~同是菜鸟路过 --------------------编程问答-------------------- --------------------编程问答-------------------- --------------------编程问答-------------------- String UserID="select * from UserMessage where UserID =" + Convert.ToInt32(e.CommandArgument.ToString())+ "";定义sql语句也没有定义成int类型的啊,是不是楼主以为这个String串它会自己执行返回一个UserID整型的数值啊。 --------------------编程问答--------------------
/// <summary>
/// 执行一条计算查询结果语句,返回查询结果(object)。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果(object)</returns>
public static object GetSingle(string SQLString)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand(SQLString, connection))
{
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SqlClient.SqlException e)
{
connection.Close();
throw e;
}
}
}
}
String strSql= "select from UserMessage where UserID =" + e.CommandArgument.ToString()+ "");
int UserID=Convert.ToInt32(GetSingle(strSql));
1、"select from UserMessage where UserID =" + Convert.ToInt32(e.CommandArgument.ToString())+ ""; 这个是字符串,可你竟然赋值给一个int,所以报错
2、select请问有问题的,select 与 from之间少了点东西的
补充:.NET技术 , C#