插入参数化查询 [英] Inserting a parameterized query

问题描述

我正在尝试使用此代码将信息插入Mysql数据库...

I am trying to insert information into Mysql database, using this code...

private void SubmitBtn_Click(object sender, EventArgs e)
        {


            SqlCommand cmd = new SqlCommand ("INSERT into [Materials Inventory] (Barcode, Material, Location, Quanitiy,  [Date Added]) VALUES ('" + textBox3.Text + "','" + textBox4.Text + "', '" + textBox5.Text + "','" + textBox6.Text + "','" + textBox7.Text + "' )",sqlcon);

            cmd.Parameters.AddWithValue("Barcode", textBox3);
            cmd.Parameters.AddWithValue("Material", textBox4);
            cmd.Parameters.AddWithValue("Location", textBox5);
            cmd.Parameters.AddWithValue("Quantity", textBox6);
            cmd.Parameters.AddWithValue("[Date Added]", textBox7);

            cmd.ExecuteNonQuery();

但运行应用程序时出现此错误

System.Data.dll中发生类型为System.InvalidOperationException的未处理异常



附加信息：ExecuteNonQuery需要一个开放且可用的连接。连接的当前状态已关闭。



我尝试过：



使用非参数化查询，

重写代码

But I get this error when running the application
An unhandled exception of type 'System.InvalidOperationException' occurred in System.Data.dll

Additional information: ExecuteNonQuery requires an open and available Connection. The connection's current state is closed.

What I have tried:

Using a non perameterized query,
Rewritting code

推荐答案

您需要打开连接而不显示您这样做。



而且，你想要的东西：

You need to open the connection and you don't show that you do.

And also, you want something along the lines of:

SqlCommand cmd = new SqlCommand ("INSERT into [Materials Inventory] (Barcode, Material, Location, Quanitiy,  [Date Added]) VALUES (@Barcode, @Material, @Location, @Quantity,  @[Date Added] )",sqlcon);

从那里开始实验。

experiment from there.

引用内联注释作为建议，请使用适当的控件命名约定，以便在控件上找到正确的控件。飞。

refer the inline comments, as an advice, Please use the proper naming convention to the controls so that it will be easy to find the correct control on the fly.

string barCode = textBox3.Text.Trim();
          string Material = textBox4.Text.Trim();
          string Location = textBox5.Text.Trim();
          string Quantity = textBox6.Text.Trim();
          string date = textBox7.Text.Trim();

          SqlCommand cmd = new SqlCommand("INSERT into [Materials Inventory] (Barcode, Material, Location, Quanitiy,  [Date Added])  " +
          " VALUES ( @Barcode,@Material,@Location,@Quantity,@Date)", sqlcon);  // add the parameter names
          cmd.Parameters.AddWithValue("@Barcode", barCode);  // parameter name with respect to the value
          cmd.Parameters.AddWithValue("@Material", Material);
          cmd.Parameters.AddWithValue("@Location", Location);
          cmd.Parameters.AddWithValue("@Quantity", Quantity);
          cmd.Parameters.AddWithValue("@Date", date);
          sqlcon.Open();  //open the connection
          cmd.ExecuteNonQuery();
          sqlcon.Close();  // close the connection

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