Question

我正在尝试创建一个命令，该命令应根据名称在textBox中键入创建表。没有错误，工作，查询看起来不错，但实际上并没有创建表。那是为什么？

private void button1_Click(object sender, EventArgs e)
{
    int count = 0;

    var connString = (@"Data Source=" + System.IO.Path.Combine(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location)) + @"\Grupe.sdf");

    using (var conn = new SqlCeConnection(connString))
    {
        try
        {
            conn.Open();
            var query = "CREATE TABLE "  + textBox1.Text.Trim() + "(" + "Id int NOT NULL IDENTITY (1,1) PRIMARY KEY" ;
            MessageBox.Show(query);

            foreach (Control c in this.Controls)
            {
                if (c.Name.Contains("temp") && c is TextBox)
                {
                    if (!String.IsNullOrEmpty(c.Text))
                    {
                        query += "," + c.Text.Trim() + " nvarchar(MAX) NULL";
                        count++;
                    }
                }
            }

            query += ")";

            var command = new SqlCeCommand(query, conn);
            command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
    }
}

Answer 1

尝试

    MessageBox.Show(query);

前

    var command = new SqlCeCommand(query, conn);

您肯定会发现语法错误。代码似乎没问题，但我想你必须看到完整的生成查询for create table。

我相信nvarchar是有/或限制为4000个字符的东西，我找不到nvarchar是支持的类型列表。使用ntext在你的代码中运行得很好。

private void button1_Click(object sender, EventArgs e)
    {
        int count = 0;
        var connString = (@"Data Source=Grupe.sdf");

        if (!File.Exists("Grupe.sdf"))
        {
            SqlCeEngine engine = new SqlCeEngine(connString);
            engine.CreateDatabase();
        }

        using (var conn = new SqlCeConnection(connString))
        {
            try
            {
                conn.Open();
                var query = "CREATE TABLE " + textBox1.Text.Trim() + "(" + "Id int NOT NULL IDENTITY (1,1) PRIMARY KEY";
                MessageBox.Show(query);
                foreach (Control c in this.Controls)
                {
                    if (c.Name.Contains("temp") && c is TextBox)
                    {
                        if (!String.IsNullOrEmpty(c.Text))
                        {
                            query += "," + c.Text.Trim() + " ntext NULL";


                            count++;
                        }
                    }


                }
                query += ")";

                MessageBox.Show(query);

                var command = new SqlCeCommand(query, conn);
                command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }

        }
    }

Answer 2

在bin / debug文件夹中查找数据库文件的副本！

创建表命令实际上并不创建表c＃

2 个答案: