C＃如何使用getschema方法获取列的列表 [英] C# how to get list of columns using getschema method

问题描述

大家好！



我正在尝试检索数据库中特定表中的列列表。以下是我到目前为止：



var dtCols = conn.GetSchema（Columns，new [] {waveform_db，null，Electrical}） ;



这是一种正确的方法吗？如果是这样，我如何访问此列表以添加到组合框？以下是我到目前为止的情况。

Hi everyone!

I am trying to retrieve a list of columns in a particular table in the database. Here is what I have so far:

var dtCols = conn.GetSchema("Columns", new[] { "waveform_db", null, "Electrical" });

Is this a proper way? If so, how can I access this list to add to a combobox? Here is what I have so far.

if (dtCols != null)
                    {
                        foreach (var dr in dtCols)
                        {
                            // code to add to combobox
                        }
                    }

编译器在foreach语句的开头就讨厌了。

foreach语句不能对system.data.datatable类型的变量进行操作，因为system.data.datatable不包含getenumerator的公开定义。



我不确定这意味着什么。有没有人对如何解决这个问题有任何暗示？



谢谢大家！

The compiler is balking at the beginning of the foreach statement.
"foreach statement cannot operate on variables of type "system.data.datatable" because "system.data.datatable" does not contain a public definition for "getenumerator".

I''m not real sure what this means. Does anyone have any hints as to how to resolve this issue?

Thanks everyone!

推荐答案

你可以这样做：

You could do it like this:

Try
    Dim SQLConnection As SqlConnection = New SqlConnection()
    SQLConnection.ConnectionString = DBconnectionWork
    Dim SQLCommand As SqlCommand = SQLConnection.CreateCommand()
    SQLCommand.CommandText = "select c.name from syscolumns c (nolock), sysobjects o (nolock) " + _
                             "where c.id = o.id and o.name = 'tablename' " + _
                             "  and c.name <> 'timestamp' " + _
                             "order by colid"
    SQLConnection.Open()
    Dim myReader As SqlDataReader = SQLCommand.ExecuteReader()
    Do While myReader.Read()
        ComboBox1.Items.Add(myReader.GetString(0))
    Loop
    myReader.Close()
    SQLConnection.Close()
Catch ex As Exception
    MsgBox(ex.ToString, MsgBoxStyle.Critical)
End Try

foreach (DataRow dr in dtCols.Rows)

您的具体错误是因为您需要迭代DataTable的行而不是DataTable本身。



但是：

Wietze Bron是正确的，他的方法正是你所需要的。

Your specific error is because you need to iterate the Rows of the DataTable not the DataTable itself.

However:
Wietze Bron is correct, his method is exactly what you need.

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