如何解决错误输入字符串不是正确的格式 [英] How Do I Resolve The Error Input String Not In Correct Format

问题描述

我给定的存储过程

Create PROCEDURE GetSalary(@Id int,@Sal money output )
AS
BEGIN
     SELECT @Sal=EmpSalary from Emp 
	where EmpId =@Id
	
END

program.cs

program.cs

SqlConnection con = new SqlConnection(Helper.ConnectionString);
             SqlCommand cmd = new SqlCommand();
             cmd.Connection = con;
             cmd.CommandText = "GetSalary";
             cmd.CommandType = CommandType.StoredProcedure;
             SqlParameter parId, parSalary;
             parId = new SqlParameter("@Id", SqlDbType.Int);
             parSalary = new SqlParameter("@Sal", SqlDbType.Money);
             parSalary.Direction = ParameterDirection.Output;
             cmd.Parameters.Add(parId);
             cmd.Parameters.Add(parSalary);
             parId.Value = int.Parse(txtId.Text);
             con.Open();
             cmd.ExecuteNonQuery();
             con.Close();
             if (parSalary.Value == DBNull.Value)
                 txtSalary.Text = "";
             else
                 txtSalary.Text = parSalary.Value.ToString();
        }

推荐答案

使用int.TryParse而不是int.Parse来处理用户输入，并尽早检查所有字段这样你就不会浪费精力去处理那些不会发生的事情。

Use int.TryParse instead of int.Parse to process user input, and check all fields as early as possible so you don't waste effort with things that aren't going to happen.

int id;
public void myMethod()
    {
    if (!int.TryParse(txtId.Text, out id))
       {
       // report input error to user
       return;
       }
    SqlConnection con = new SqlConnection(Helper.ConnectionString);
    SqlCommand cmd = new SqlCommand();
    cmd.Connection = con;
    ...

然后在参数中使用经过检查并且罚款 id 的值



我建议你改为使用AddWithValue：

Then use the checked-and-fine id value in your parameters

I would suggest though, that you use AddWithValue instead:

cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@Id", id);

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