C# DataGridView 不会在数据库中更新

Question

我创建了一个组合框，其中显示了我数据库中所有表的名称。当我单击一个按钮时，当前表显示在 DataGridView 中。我已经成功创建了一个插入按钮来在当前表中添加新数据，但它不会更新我数据库中的信息......这是代码：

private void insertBttn_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(@"Data Source=NUC\MICROGARDE;Initial Catalog=SQL;Integrated Security=True");

         int i = 0;
  //     SqlDataAdapter sda;

        con.Open();

        for (i = 0; i < this.dataGridView1.Rows.Count; i++)
        { 
            string query = "insert into " + comboBox1.SelectedValue.ToString() + " (@" + dataGridView1.Columns[i] + ") VALUES ('" + this.dataGridView1.Columns[i] + "');";

            SqlCommand cmd = new SqlCommand(query, con);
        }

        con.Close();

Answer 1

基本上你缺少两个关键结构：

• 1、添加参数
• 2、执行查询

您的代码已编辑：

    private void insertBttn_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(@"Data Source=NUC\MICROGARDE;Initial Catalog=SQL;Integrated Security=True");

        int i = 0;
        con.Open();
        for (i = 0; i < this.dataGridView1.Rows.Count; i++)
        { 
            string query = "insert into " + comboBox1.SelectedValue.ToString() + " (@" + dataGridView1.Columns[i] + ") VALUES ('" + this.dataGridView1.Columns[i] + "');";
            SqlCommand cmd = new SqlCommand(query, con);
            cmd.Parameters.Add(new SqlParameter(@Field, "value"));
            cmd.Parameters.Add(new SqlParameter(@Field, "value"));
            cmd.ExecuteNonQuery();
        }
        con.Close();
     }

使用参数也可以阻止 SQL 注入。

Answer 2

更改您的代码并检查

protected void insertBttn_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
        int i = 0;
        int j = 0;
        string query = "";
        string columnText = "";
        string valueText = "";

        SqlCommand cmd = new SqlCommand();
        cmd.CommandType = System.Data.CommandType.Text;
        cmd.Connection = con;

        for (i = 0; i < dataGridView1.Rows.Count; i++)
        {
            columnText = "";
            valueText = "";
            for (j = 0; j < dataGridView1.Rows[0].Cells.Count; j++)
            {
                if (j != 0)
                {
                    columnText += ",";
                    valueText += ",";
                }
                columnText += dataGridView1.HeaderRow.Cells[j].Text;
                valueText += "'" + dataGridView1.Rows[i].Cells[j].Text + "'";   
            }
            query += "insert into " + comboBox1.SelectedValue.ToString() + " (" + columnText + ") values (" + valueText + ")";
        }

        try
        {
            cmd.CommandText = query;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
        catch (Exception ex)
        {
            Response.Write(ex.Message.ToString());
        }
        finally
        {
            con.Close();
        }          

    }