从C＃中的存储过程中获取一点值

The situation is following, i have a stored procedure in SQL Server , this has a few output parameters, one of them is a bit type, what I want is to take the value of that parameter, but I have a conversion error, InvalidCastException.

情况如下，我在SQL Server中有一个存储过程，这里有一些输出参数，其中一个是位类型，我想要的是取该参数的值，但我有一个转换错误，InvalidCastException。

This is my code:

这是我的代码：

public void exec()
       {
            String strConnString = "Server=.\\SQLEXPRESS;Database=recalls;Integrated Security=true";
            SqlConnection con = new SqlConnection(strConnString);
            SqlCommand cmd = new SqlCommand();
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.CommandText = "findVinCamp";
            int c = Int32.Parse(campaing.Text);
            cmd.Parameters.Add("@camp", SqlDbType.Int).Value = c;
            cmd.Parameters.Add("@vin", SqlDbType.VarChar, 100).Value = vin.Text;
            cmd.Parameters.Add("@desc", SqlDbType.NVarChar, 255).Direction = ParameterDirection.Output;
            cmd.Parameters.Add("@st", SqlDbType.VarChar, 50).Direction = ParameterDirection.Output;
            cmd.Parameters.Add("@bit", SqlDbType.Bit).Direction = ParameterDirection.Output;
            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            bit = (int)cmd.Parameters["@bit"].Value; //Exception Here
            if (bit == 1)
            {
                desc.Text = cmd.Parameters["@desc"].Value.ToString();
                stt.Text = cmd.Parameters["@st"].Value.ToString();
                camp = cmd.Parameters["@camp"].Value.ToString();
                if (stt.Text.Equals("APPLIED"))
                {
                    stt.ForeColor = System.Drawing.Color.LawnGreen;
                }
                else
                {
                    stt.ForeColor = System.Drawing.Color.Firebrick;
                    label3.Enabled = true;
                    newstatus.Enabled = true;
                    update.Enabled = true;
                }
            }
            else
            {
                MessageBox.Show("Doesn't exits!");
            }
    }

I'm trying to assign the bit parameter to a int variable. Any question post on comments.

我正在尝试将bit参数分配给int变量。关于评论的任何问题。

4 个解决方案

#1

I change the (int) to this, now works perfectly:

我将（int）更改为this，现在完美运行：

Boolean lol = Convert.ToBoolean(cmd.Parameters["@bit"].Value);

#2

Use this following Line

使用以下行

bool isConfirmed = (bool)cmd.Parameters["@bit"].Value;
if(isConfirmed ){
                desc.Text = cmd.Parameters["@desc"].Value.ToString();
                stt.Text = cmd.Parameters["@st"].Value.ToString();
                camp = cmd.Parameters["@camp"].Value.ToString();
                if (stt.Text.Equals("APPLIED"))
                {
                    stt.ForeColor = System.Drawing.Color.LawnGreen;
                }
                else
                {
                    stt.ForeColor = System.Drawing.Color.Firebrick;
                    label3.Enabled = true;
                    newstatus.Enabled = true;
                    update.Enabled = true;
                }

}
else{
MessageBox.Show("Doesn't exits!");
}

**UPDATE: **if the bit column allows nulls -- many ways you can do this

**更新：**如果位列允许空值 - 您可以通过多种方式执行此操作

bool isConfirmed = cmd.Parameters["@bit"].Value as bool? ?? null;

and also read this- SQL Server Data Types and Their .NET Framework Equivalents

并阅读本文 - SQL Server数据类型及其.NET Framework等价物

#3

I believe a bit will convert to a boolean. Which should make your code a bit simpler too.

我相信有点会转换为布尔值。哪个应该使您的代码更简单一些。

i.e.

即

...
var bit = (bool)cmd.Parameters["@bit"].Value;
if (bit)
{
...

#4

You are trying to convert your boolean output to INT, please convert it in Boolean:

您正在尝试将布尔输出转换为INT，请将其转换为布尔值：

bool bitValue= Convert.ToBoolean(cmd.Parameters["@bit"].Value)

#1