它在SQL数据库中显示System.Data.DataRowView [英] It's showing System.Data.DataRowView in SQL database

问题描述

 private void button_Pass_Click（object sender，EventArgs e）
 {
 
 SqlConnection con1 = new SqlConnection（Data Source = .\\SQLEXPRESS; Initial Catalog = db-ub; Integrated Security = True）; 
 
 SqlCommand cmd1 =新的SqlCommand（插入访问者（To_Whom）值（@whom），con1）; 
 con1.Open（）; 
 int o = cmd1.ExecuteNonQuery（）; 
 MessageBox.Show（o +：已插入记录）; 
 
} 
 private void Form3_Load（object sender，EventArgs e）
 {
 SqlConnection con = new SqlConnection（Data Source = .\\SQLEXPRESS; Initial Catalog = db-ub; Integrated Security = True）; 
 con.Open（）; 
 
 SqlCommand sc = new SqlCommand（从Employees中选择Employee_Name，con）; 
 SqlDataReader阅读器; 
 
 reader = sc.ExecuteReader（）; 
 DataTable dt = new DataTable（）; 
 
 
 dt.Columns.Add（Employee_Name，typeof（string））; 
 dt.Load（读者）; 
 comboBox_TOWHOM.DataSource = dt; 
 comboBox_TOWHOM.DisplayMember =Employee_Name; 
 
 con.Close（）; 
} 
 
 
（/ *我有两个表访客和员工，我有Employee_Name。在我的form3中有一个组合框，它从员工将表存储到访客表中。一切都很好，但在访客表中，它显示To_Whom列下的System.Data.DataRowView。请帮助。* /）

解决方案

你有这个：

 SqlConnection con1 = new SqlConnection（ 数据源=。\\SQLEXPRESS;初始目录= db-ub;集成安全性=真）; 
 
 SqlCommand cmd1 =新的SqlCommand（ 插入访问者（To_Whom）值（@whom） ，con1）; 
 con1。打开（）; 
  int  o = cmd1.ExecuteNonQuery（）; 

你告诉sql期望一个参数但从未提供参数的地方。



您需要添加

 cmd1.Parameters.AddWithValue（  @ which，someValue）; 

。

private void button_Pass_Click(object sender, EventArgs e)
{

SqlConnection con1 = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=db-ub;Integrated Security=True");

SqlCommand cmd1 = new SqlCommand("Insert into Visitors(To_Whom) values (@whom)", con1);
con1.Open();              
int o = cmd1.ExecuteNonQuery();
MessageBox.Show(o + " :Record has been inserted");

}
private void Form3_Load(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=db-ub;Integrated Security=True");
            con.Open();
            
            SqlCommand sc = new SqlCommand("select Employee_Name from Employees",con);
            SqlDataReader reader;

            reader = sc.ExecuteReader();
            DataTable dt = new DataTable();

           
            dt.Columns.Add("Employee_Name", typeof(string));
            dt.Load(reader);
            comboBox_TOWHOM.DataSource = dt;
            comboBox_TOWHOM.DisplayMember = "Employee_Name";

              con.Close();
}


(/*I have two tables "Visitors" and "Employees", I have Employee_Name. In my form3 there is a combobox which is fetching data from the "Employees" table and storing it to the "Visitors" table. Everything is fine but in the "Visitors" table it’s showing "System.Data.DataRowView" under To_Whom column. Please help. */)

解决方案

You have this:

SqlConnection con1 = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=db-ub;Integrated Security=True");
 
SqlCommand cmd1 = new SqlCommand("Insert into Visitors(To_Whom) values (@whom)", con1);
con1.Open();              
int o = cmd1.ExecuteNonQuery();

where you told the sql to expect a parameter but then never supplied the parameter.

You need to add

cmd1.Parameters.AddWithValue("@whom", someValue);

before you call ExecuteNonQuery.

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