c 如何创建组合框

在C语言中创建一个组合框（ComboBox）通常需要使用图形用户界面库，比如GTK+、Qt或者Win32 API。以下我将分别给出使用GTK+和Win32 API创建组合框的示例。

使用GTK+创建组合框

在GTK+中，组合框是通过`GtkComboBox`来实现的。以下是一个简单的例子：

```c

include

static void activate(GtkApplication app, gpointer user_data) {

GtkWidget window;

GtkWidget combo_box;

GtkWidget combo_box_text;

GtkWidget vbox;

window = gtk_application_window_new(app);

gtk_window_set_title(GTK_WINDOW(window), "ComboBox Example");

gtk_window_set_default_size(GTK_WINDOW(window), 200, 100);

vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 5);

gtk_container_add(GTK_CONTAINER(window), vbox);

combo_box = gtk_combo_box_new_text();

gtk_combo_box_set_active(GTK_COMBO_BOX(combo_box), 0); // 设置默认选中的项

combo_box_text = gtk_combo_box_text_new();

gtk_combo_box_text_append_text(GTK_COMBO_BOX_TEXT(combo_box_text), "Option 1");

gtk_combo_box_text_append_text(GTK_COMBO_BOX_TEXT(combo_box_text), "Option 2");

gtk_combo_box_text_append_text(GTK_COMBO_BOX_TEXT(combo_box_text), "Option 3");

gtk_combo_box_set_model(GTK_COMBO_BOX(combo_box), GTK_TREE_MODEL(combo_box_text));

gtk_container_add(GTK_CONTAINER(vbox), combo_box);

gtk_widget_show_all(window);