'System.Data.DataRowView' in DropDownList

本文关键字：DropDownList in System Data DataRowView | 更新日期: 2023-09-27 18:22:49

我无法将数据绑定到Dropdown List。。有人能解释我为什么吗？错误为：'System.Data.DataRowView' does not contain a property with the name '_DeptID'.我的代码是：

public class ClassDataManagement
{
    public DataTable BindDropDownList(string Sql, DropDownList DropDownList)
    {
        SqlConnection cn = new SqlConnection(@"Data Source=ABID-PC;Initial Catalog=_uniManagement;Integrated Security=True");
        SqlCommand cmd = new SqlCommand(Sql, cn);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        if (dt.Rows.Count == 0)
        {
        }
        else
        {
            DropDownList.DataTextField = "Name";
            DropDownList.DataValueField = "_DeptID";
            DropDownList.DataSource = dt.DefaultView;
            DropDownList.DataBind();
        }
        return dt;
    }
}
protected void Page_Load(object sender, EventArgs e)
{
    ClassDataManagement dm = new ClassDataManagement();
    dm.BindDropDownList("select _Program.Name from _program,_Department where _program._Deptid = _department._DeptId", DropDownListProgram);
}

'System.Data.DataRowView' in DropDownList

您不会在SQL语句中返回名为_Deptid的列。

您的SQL语句应为：

select _program.Name, _program._Deptid 
  from _program,_Department 
 where _program._Deptid = _Department._DeptId

正如Stackoverflow User所提到的，通过使用using语句，这将自动处理对象。你正在做的另一件事：

if (dt.Rows.Count == 0)

但你里面没有代码。无论你是否在实际代码中这样做，但如果你打算将其留空，最好这样做：

if (dt.Rows.Count > 0)
{
    DropDownList.DataTextField = "Name";    
    DropDownList.DataValueField = "_DeptID";    
    DropDownList.DataSource = dt.DefaultView;    
    DropDownList.DataBind();
}
  1. select语句中缺少列_Dept

  2. 缺少对对象的处理。所以你可以用两种方式

    （a） 手动处理

    （b） 使用语句

public class ClassDataManagement
{
    public DataTable BindDropDownList(string Sql, DropDownList DropDownList)
    {
        using (SqlConnection cn = new SqlConnection(@"Data Source=ABID-PC;Initial Catalog=_uniManagement;Integrated Security=True"))
        {
            using (SqlCommand cmd = new SqlCommand(Sql, cn))
            {
                using(SqlDataAdapter da = new SqlDataAdapter(cmd))
                {
                    using (DataTable dt = new DataTable())
                    {
                        da.Fill(dt);
                        DropDownList.DataTextField = "Name";
                        DropDownList.DataValueField = "_Deptid";
                        DropDownList.DataSource = dt.DefaultView;
                        DropDownList.DataBind();
                        return dt;
                    }
                }
            }
        }
    }
}
protected void Page_Load(object sender, EventArgs e)
{
    ClassDataManagement dm = new ClassDataManagement();
    dm.BindDropDownList("select _Program.Name, _program._Deptid from _program,_Department "
        + "where _program._Deptid = _department._DeptId", DropDownListProgram);
}

编辑-1

为SqlDataAdapter以及

添加Using语句

将SQL更改为：

select _Program.Name, _Program._DeptId from _program,_Department where _program._Deptid = _department._DeptId

尝试将代码修改为这样，您缺少_DeptID

   protected void Page_Load(object sender, EventArgs e)
    {
        ClassDataManagement dm = new ClassDataManagement();
        dm.BindDropDownList("select _Program.Name,_DeptID from _program,_Department where _program._Deptid = _department._DeptId", DropDownListProgram);
    }
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