c# - 组合框和System.Data.DataRowView

我有一个在打开主窗体时调用的方法

private void populateComboBoxes()
{
    SqlCeDataAdapter breakfastAdapter = new SqlCeDataAdapter("SELECT DISTINCT recipeName FROM Recipe WHERE Category = 'breakfast' ", databaseConnection);
    SqlCeDataAdapter lunchAdapter = new SqlCeDataAdapter("SELECT DISTINCT recipeName FROM Recipe WHERE Category = 'lunch' ", databaseConnection);
    breakfastAdapter.Fill(breakfastDS, "Recipe");
    lunchAdapter.Fill(lunchDS, "Recipe");
    cmbBox1.DisplayMember = "recipeName";
    cmbBox1.ValueMember = "recipeName";
    cmbBox1.DataSource = breakfastDS.Tables["Recipe"];
    cmbBox2.DataSource = lunchDS.Tables["Recipe"];
    cmbBox2.DisplayMember = "recipeName";
    cmbBox2.ValueMember = "recipeName";
}

它基本上基于select语句填充两个组合框。一旦此方法命中cmbBox1.DataSource = breakfastDS.Tables["Recipe"]则停止执行并移到此方法：

private void cmbBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    rtbPicture.Visible = false;
    string qry = "";
    qry = "SELECT DISTINCT ingredientName FROM Recipe WHERE recipeName = " + cmbBox1.SelectedItem.ToString();

    SqlCeCommand com = new SqlCeCommand(qry, databaseConnection);
    com.CommandText = qry;
    rtbRecipe.Text = com.ExecuteScalar().ToString();
}

此方法应该执行select语句并将该信息放入richtextbox，但由于某些原因，未设置cmbBox1。根据我的理解，第一个combobox已经在前面的方法中设置了display和value成员。但是，当我到达cmbBox1.SelectedItem.ToString()时，它返回System.Data.DataRowView而不是combobox中的实际字符串。我不知道为什么它给我System.Data.DataRowView而不是字符串。

最佳答案

您正在使用cmbBox1.SelectedItem.ToString()。
您可能应该改用SelectedValue：

qry = "SELECT DISTINCT ingredientName FROM Recipe WHERE recipeName = " + cmbBox1.SelectedValue.ToString();

SelectedItem获取实际的ComboBox项（在本例中为aDataRowView），而SelectedValue获取指定为ValueMember的ComboBox属性的值。

关于c# - 组合框和System.Data.DataRowView，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/15625479/