编写一个代码需要帮助 [英] Need help in writing one code

问题描述

大家好



我为组合框编写了以下代码

Hi all

I wrote the below code for a comboBox

if (comboBox1.Text == "Name")
            {
                SqlCommand cmd = new SqlCommand("select name from details",con);
                con.Open();

现在我想将结果添加到另一个组合框



假设查询结果为

a

b

c

then它应该显示在第二个组合框中..



请告诉我如何将结果绑定到第二个comboBox

Now i want to add the result to another comboBox

Suppose the result of the query comes as
a
b
c
then it should show in the second comboBox..

please tell me how to bind the result to the second comboBox

推荐答案

if (comboBox1.Text == "Name")
            {
                string cmd = "select * from details";
                SqlDataAdapter da = new SqlDataAdapterh(cmd, con);
                DataTable dt =  new DataTable();
                dah.fill(dt);

                foreach(DataRow dr in dt.Rows)
                {
                   comboBox2.Items.Add(dr["name"].ToString());
                }
            }

首先，您需要执行命令对象。您可以使用Execute方法实现此目的。完整示例如下：

Firstof all you need to execute your command object. You can achieve that with Execute method. A full example follows:

public DateTime GetServerDate()
        {
            using (SqlConnection cn = new SqlConnection(ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand(@"SELECT GETDATE()", cn))
                {
                    cn.Open();

                    return (DateTime)cmd.ExecuteScalar();
                }
            }
        }

在这个例子中我们调用 ExecuteScalar 方法。它将仅返回所获取数据的第一行的第一列。您可以在此处找到有关它的更多信息： http://msdn.microsoft .com / zh-cn / library / system.data.sqlclient.sqlcommand.executescalar.aspx [ ^ ]
SqlCommand对象还提供其他方法 ExecuteReader（） 和 ExecuteNonQuery（）。

基本上你会调用ExecuteReader（）方法，然后将结果绑定到你的组合。

In this example we are calling ExecuteScalar method. It will return only the first column of first row of the fetched data. More information about it you can find here: http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executescalar.aspx[^]
SqlCommand object offers also other methods as ExecuteReader() and ExecuteNonQuery().
Basically you will call ExecuteReader() method and then bind the result to your combo.

[DataObject(true)]
public class DataService
{
/// <summary>
/// Retrives all the detail data
/// </summary>
/// <returns>Datatable contining the requested data.</returns>
public static DataTable GetAllByDetail()
{
    DataTable table = new DataTable();

    using (SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("select name from details", cn))
        {
            cn.Open();

            using (SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
                table.Load(reader);
            }
        }
    }

    return table;
}
}

现在你可以调用这个方法，并将数据绑定到你的组合。 />

Now you can call this method, and bind the data to your combo.

private DataTable dt = DataService.Retrieve();

ComboBox1.DataSource = dt; 
ComboBox1.DisplayMember = "Name"; 
ComboBox1.ValueMember = "Name";

我希望这能解答你所有的疑惑。



干杯

I hope this answers all of your doubts.

Cheers

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