Visual Studio beschwert sich: Warnung 1 Der Designer muss eine Instanz des Typs 'RentalEase.CustomBindingNavForm' erstellen, aber nicht, da der Typ als abstrakt deklariert ist .Der Designer muss eine Instanz erstellen ... kann nicht, weil der Typ als abstrakt deklariert wird
Visual Studio lässt mich nicht auf den Designer für das Formular zugreifen. Die Klasse implementiert bereits alle abstrakten Methoden aus dem CustomBindingNavForm. CustomBindingNavForm stellt einige Funktionen konkret und abstrakt zur Verfügung.
Gibt es einen Weg um dies? Hier
ist die Klasse:
public abstract class CustomBindingNavForm : SingleInstanceForm {
//Flags for managing BindingSource
protected bool isNew = false;
protected bool isUpdating = false;
/// <summary>
/// This is so that when a new item is added, it sets isNew and firstPass to true. The Position Changed Event will look for
/// firstPass and if it is true set it to false. Then on the next pass, it will see it's false and set isNew to false.
/// This is needed because the Position Changed Event will fire when a new item is added.
/// </summary>
protected bool firstPass = false;
protected abstract bool validateInput();
protected abstract void saveToDatabase();
//manipulating binding
protected abstract void bindingSourceCancelResetCurrent();
protected abstract void bindingSourceRemoveCurrent();
protected abstract void bindingSourceMoveFirst();
protected abstract void bindingSourceMoveNext();
protected abstract void bindingSourceMoveLast();
protected abstract void bindingSourceMovePrevious();
protected abstract void bindingSourceAddNew();
public void bindingNavigatorMovePreviousItem_Click(object sender, EventArgs e) {
if (validateInput()) {
bindingSourceMovePrevious();
} else {
DialogResult cont = MessageBox.Show(null, "There are errors in your data. Click Cancel to go back and fix them, or ok to continue. If you continue, changes will not be saved.", "Continue?", MessageBoxButtons.OKCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);
if (cont == DialogResult.OK) {
if (isNew) {
bindingSourceRemoveCurrent();
isNew = false;
} else {
bindingSourceCancelResetCurrent();
bindingSourceMovePrevious();
}
}
}
}
public void bindingNavigatorAddNewItem_Click(object sender, EventArgs e) {
if (validateInput()) {
saveToDatabase();
bool temp = isUpdating;
isUpdating = true;
bindingSourceAddNew();
isUpdating = temp;
isNew = true;
firstPass = true;
} else {
DialogResult cont = MessageBox.Show(null, "There are errors in your data. Click Cancel to go back and fix them, or ok to continue. If you continue, changes will not be saved.", "Continue?", MessageBoxButtons.OKCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);
if (cont == DialogResult.OK) {
if (isNew) {
bindingSourceRemoveCurrent();
isNew = false;
} else {
bindingSourceCancelResetCurrent();
}
bool temp = isUpdating;
isUpdating = true;
bindingSourceAddNew();
isUpdating = temp;
isNew = true;
firstPass = true;
}
}
}
public void bindingNavigatorMoveFirstItem_Click(object sender, EventArgs e) {
if (validateInput()) {
bindingSourceMoveFirst();
} else {
DialogResult cont = MessageBox.Show(null, "There are errors in your data. Click Cancel to go back and fix them, or ok to continue. If you continue, changes will not be saved.", "Continue?", MessageBoxButtons.OKCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);
if (cont == DialogResult.OK) {
if (isNew) {
bindingSourceRemoveCurrent();
isNew = false;
} else {
bindingSourceCancelResetCurrent();
}
bindingSourceMoveFirst();
}
}
}
public void bindingNavigatorMoveNextItem_Click(object sender, EventArgs e) {
if (validateInput()) {
bindingSourceMoveNext();
} else {
DialogResult cont = MessageBox.Show(null, "There are errors in your data. Click Cancel to go back and fix them, or ok to continue. If you continue, changes will not be saved.", "Continue?", MessageBoxButtons.OKCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);
if (cont == DialogResult.OK) {
if (isNew) {
bindingSourceRemoveCurrent();
isNew = false;
} else {
bindingSourceCancelResetCurrent();
}
bindingSourceMoveNext();
}
}
}
}
möglich Duplikat [Wie kann ich Visual Studio 2008 Windows Forms Designer erhalten Sie ein Formular zu machen, die eine abstrakte Basisklasse implementiert?] (Http://stackoverflow.com/questions/1620847/how-can -i-get-visual-studio-2008-windows-forms-designer-zu-render-a-form-das-im) –