Question

我在表单上有一个组合框控件，可以从某个数据源中提取数据（显示和值）。另一方面，我有一排桌子。我想在app发布时，组合框将selectedvalue或selecteditem设置为上一行中一列的值。当用户更改了组合框时，它将持续更改为行。我试图将SelectedValue绑定到此列，但它不起作用。 Combobox只是开始第一项。什么问题？

修改

这是一个Win Forms项目。这是绑定代码：

this.comboBoxCountries = new System.Windows.Forms.ComboBox();
this.countriesBindingSource = new System.Windows.Forms.BindingSource(this.components);

// 
// comboBoxCountries
// 
this.comboBoxCountries.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.searchCriteriaBindingSource, "Postcode", true));
this.comboBoxCountries.DataBindings.Add(new System.Windows.Forms.Binding("SelectedValue", this.searchCriteriaBindingSource, "CountryCode", true));
this.comboBoxCountries.DataSource = this.countriesBindingSource;
this.comboBoxCountries.DisplayMember = "Name";
this.comboBoxCountries.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
this.comboBoxCountries.FormattingEnabled = true;
this.comboBoxCountries.Location = new System.Drawing.Point(190, 19);
this.comboBoxCountries.Name = "comboBoxCountries";
this.comboBoxCountries.Size = new System.Drawing.Size(156, 21);
this.comboBoxCountries.TabIndex = 2;
this.comboBoxCountries.ValueMember = "Code";
this.comboBoxCountries.SelectedValueChanged += new System.EventHandler(this.comboBoxCountries_SelectedValueChanged);

// 
// countriesBindingSource
// 
this.countriesBindingSource.DataMember = "Countries";
this.countriesBindingSource.DataSource = this.dbDataSetCountries;
// 
// dbDataSetCountries
// 
this.dbDataSetCountries.DataSetName = "dbDataSetCountries";
this.dbDataSetCountries.SchemaSerializationMode = System.Data.SchemaSerializationMode.IncludeSchema;

// 
// searchCriteriaBindingSource
// 
this.searchCriteriaBindingSource.AllowNew = false;
this.searchCriteriaBindingSource.DataMember = "SearchCriteria";
this.searchCriteriaBindingSource.DataSource = this.dbDataSetSearchCriteria;
this.searchCriteriaBindingSource.BindingComplete += new System.Windows.Forms.BindingCompleteEventHandler(this.searchCriteriaBindingSource_BindingComplete);
// 
// dbDataSetSearchCriteria
// 
this.dbDataSetSearchCriteria.DataSetName = "dbDataSetSearchCriteria";
this.dbDataSetSearchCriteria.SchemaSerializationMode = System.Data.SchemaSerializationMode.IncludeSchema;

EDIT2

正如我在下面的评论中提到的，我有另一个textbox与另一个DataMember相同的绑定源绑定，textbox正常工作。它看起来具有适当的价值。当我在同一个数据库上更改DataMember时，我设置了组合框绑定的selectedvalue属性，它也显示了良好的结果并且正常工作。

提前致谢！

Answer 1

查看组合框的 DisplayMember 和 ValueMember 属性。您需要告诉ComboBox数据源中的哪个成员要显示在下拉列表中，以及在请求SelectedValue时要给出的值。

听起来你的ComboBox被绑定到一个静态列表，而你的行却没有。您可以考虑使用将ComboBox和DataGridView的DataSource设置为的BindingSource。这样，当DGV导航到新行时，ComboBox将使用新行的值进行更新。

以下是MSDN上ComboBox的链接：http://msdn.microsoft.com/en-us/library/system.windows.forms.combobox.aspx

Answer 2

我发现了。因此，对于使用此问题进行管理，您应该从visual studio数据绑定菜单中删除SelectedValue数据绑定，并在填充所有绑定源之后放置适当的代码以在某个位置添加此数据绑定：

private void MainForm_Load_1(object sender, EventArgs e)
{
    this.searchCriteriaTableAdapter1.Fill(this.dbDataSetCountries.SearchCriteria);    

    this.searchCriteriaTableAdapter.Fill(this.dbDataSetSearchCriteria.SearchCriteria);    

    comboBoxCountries.DataBindings.Add("SelectedValue", this.dbDataSetCountries.SearchCriteria, "CountryCode");                
}

ComboBox数据绑定

2 个答案: