数据源需要具备哪些条件才能使 GridView 自动生成列

Question

我创建了自定义数据类型类，以我需要的方式格式化数据。我从数据库中检索的数据是 .NET 基类型，因此我需要遍历 DataTable，将每个项转换为其自定义类型，然后将转换后的项放入新表中。我还将列名从旧表复制到新表。问题是，当我将 GridView 绑定到新表时，它会引发异常：

HttpException:  
The data source for GridView with id 'TestGrid' did not have any properties
or attributes from which to generate columns.  Ensure that your data source 
has content.  
Stack Trace:
at System.Web.UI.WebControls.GridView.CreateAutoGeneratedColumns(PagedDataSource dataSource)
at System.Web.UI.WebControls.GridView.CreateColumns(PagedDataSource dataSource, Boolean useDataSource)
at System.Web.UI.WebControls.GridView.CreateChildControls(IEnumerable dataSource, Boolean dataBinding)
at System.Web.UI.WebControls.CompositeDataBoundControl.PerformDataBinding(IEnumerable data)
at System.Web.UI.WebControls.GridView.PerformDataBinding(IEnumerable data)
at System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data)
at System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback)
at System.Web.UI.WebControls.DataBoundControl.PerformSelect()
at System.Web.UI.WebControls.BaseDataBoundControl.DataBind()
at System.Web.UI.WebControls.GridView.DataBind()

我需要向数据表添加什么才能使自动生成列正常工作？

编辑：这是数据表的代码：

     // Populate first DataTable with data from database.
     adapter = new DataAdapter("SELECT status, date_ordered, date_due FROM import_table", OpenConnection);
     DataTable originalTable = new DataTable();
     adapter.Fill(originalTable)
     // Second DataTable for converted table data.
     DataTable convertedTable = new DataTable();
     // The list of custom datatypes to convert to.
     Type[] newTypes = {typeof(TrackingStatus), typeof(Date), typeof(Date)};
     // Set the ColumnName and DataType on each column of the new table.
     for(int i = 0; i < originalTable.Columns.Count; i++)
     {
        convertedTable.Columns.Add();
        convertedTable.Columns[i].ColumnName = originalTable.Columns[i].ColumnName;
        if(newTypes.Length > i)
           convertedTable.Columns[i].DataType = newTypes[i];
     }
     // Convert each item from the old table and add it to the new table.
     foreach(DataRow oldRow in originalTable.Rows)
     {
        DataRow newRow = convertedTable.NewRow();
        for(int i = 0; i < convertedTable.Columns.Count; i++)
        {
           if(newTypes.Length <= i)
              newRow[i] = oldRow[i];
           else if(newTypes[i] == typeof(Date))
              newRow[i] = Date.FromObject(oldRow[i]);
           else if(newTypes[i] == typeof(TrackingStatus))
              newRow[i] = TrackingStatus.FromObject(oldRow[i]);
           else if(newTypes[i] == typeof(EmailAddress))
              newRow[i] = EmailAddress.FromObject(oldRow[i]);
        }
        convertedTable.Rows.Add(newRow);
     }
     // Bind the GridView.
     displayGrid.DataSource = convertedTable;
     displayGrid.DataBind();

Answer 1

将每个数据表转换为自定义类型时，不要创建新的数据表，而是创建一个新的列表并将列表绑定到数据源。

例如

var list = new List<MyClass>();
var myType = //Convert your type
list.Add(myType);
grid.DataSource = list;

当然，这一切都只是如何做到这一点的想法。

更新：之后看到了你的代码：

试试这个：

创建一个名为 ImportRow 的类

class ImportRow
{
    private string m_Status = string.Empty;
    private DateTime m_DateOrdered;
    private DateTime m_DateDue;
    public ImportRow() { }
    public string Status
    {
        get { return m_Status; }
        set { m_Status = value; }
    }
    public DateTime DateOrdered
    {
        get { return m_DateOrdered; }
        set { m_DateOrdered = value; }
    }
    public DateTime DateDue
    {
        get { return m_DateDue; }
        set { m_DateDue = value; }
    }
}

然后将其用作：

        var importedData = new List<ImportRow>();
        foreach (DataRow oldRow in originalTable.Rows)
        {
            var newRow = new ImportRow();
            newRow.Status = oldRow["status"].ToString();
            newRow.DateDue = Convert.ToDateTime(oldRow["date_due"].ToString());
            newRow.DateOrdered = Convert.ToDateTime(oldRow["date_ordered"].ToString());
            importedData.Add(newRow);
        }

然后

 displayGrid.DataSource = importedData;
 displayGrid.DataBind();

Answer 2

自定义类型需要如下公共属性：

public class Foo
{
    public int Id;
    public string Name;
}

或者您需要将DataTable本身用作DataSource。