多个部分的标识符"System.Data.DataRowView"被指定为"System.Data.DataRowView".不能被束缚 [英] The multi-part identifier "System.Data.DataRowView" could not be bound

问题描述

我有一个填充Combobox1的表，而Combobox1应该填充Combobox2，这就是问题所在. 那是我得到的例外

I have a table that populate Combobox1 and Combobox1 should populate Combobox2 and this is where the problem is. That's the exception i'm getting

无法绑定多部分标识符"System.Data.DataRowView".

The multi-part identifier "System.Data.DataRowView" could not be bound.

代码:

    private void frm2_Load(object sender, EventArgs e)
    {
        //Populate Combobox1
        SqlDataAdapter da = new SqlDataAdapter("SELECT CategoryID, Name FROM Categories", clsMain.con);
        DataSet ds = new DataSet();
        da.Fill(ds);
        comboBox1.DataSource = ds.Tables[0];
        comboBox1.DisplayMember = "Name";
        comboBox1.ValueMember = "CategoryID";
    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        //populate Combobox2
        SqlDataAdapter da = new SqlDataAdapter("SELECT SubCategoryID, Name FROM SubCategories WHERE CategoryID=" + comboBox1.SelectedValue, clsMain.con);
        DataSet ds = new DataSet();
        da.Fill(ds);
        comboBox2.DataSource = ds.Tables[0];
        comboBox2.DisplayMember = "Name";
        comboBox2.ValueMember = "SubCategoryID";
    }

推荐答案

这是由于在第一个组合中填充数据时加载了第二个组合框.
您可以通过以下方法避免此错误:
1.使用 SelectionChangeCommitted 事件而不是 SelectedIndexChanged 事件.
或
2.分离选定的索引更改事件，填充组合框，然后再次将事件附加为:

This is due to loading second combobox while filling data in first combo.
You can avoid this error by:
1. Use SelectionChangeCommitted event instead of SelectedIndexChanged event.
Or
2. Detach selected index change event, populate combobox, attach event again as:

private void frm2_Load(object sender, EventArgs e)
{
   //Detach event
   comboBox1.SelectedIndexChanged -= comboBox1_SelectedIndexChanged;

    //Populate Combobox1
    SqlDataAdapter da = new SqlDataAdapter("SELECT CategoryID, Name FROM Categories", clsMain.con);
    DataSet ds = new DataSet();
    da.Fill(ds);
    comboBox1.DataSource = ds.Tables[0];
    comboBox1.DisplayMember = "Name";
    comboBox1.ValueMember = "CategoryID";

   //Attach event again
    comboBox1.SelectedIndexChanged += comboBox1_SelectedIndexChanged;
}

希望这会对您有所帮助.

Hopes this will help you.

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