Question

我已经从另一个类中实例化了一个对象，以便使用该类的属性。在按钮事件中一切正常，但是，在按钮事件之外我得到一个错误，告诉我我的实例化对象被用作类型。如果我使用相同的代码并将其剪切并粘贴到按钮事件中，我不会收到错误消息。我不明白发生了什么以及为什么。该对象是实例化的，无论它是在按钮事件的内部还是外部，为什么它不在按钮事件之外工作？一旦表单打开，我需要从另一个表单自动填充这两个标签字段，而不是单击按钮时。

这是我的代码：

public partial class MeasurementsForm : Form
{
    private MeasurementsBOL busObject = new MeasurementsBOL();

    //autofill bodyfat and body weight from nutrition form when form opens
    busObject.BodyFatB4 = double.Parse(lblBodyFatB4FromNutrition.Text);
    busObject.BodyWeightB4 = double.Parse(lblWeightB4FromNutrition.Text);

    //default constructor
    public MeasurementsForm()
    {
        InitializeComponent();
        busObject.InitializeConnection();
    }        

    //event handler for B4 input data
    private void btnEnterMeasurementsB4_Click(object sender, EventArgs e)
    {


        //convert input data and assign to variables
        busObject.ChestMeasurementB4 = double.Parse(txtChestB4.Text);
        busObject.WaistMeasurementB4 = double.Parse(txtWaistB4.Text);
        busObject.HipsMeasurementB4 = double.Parse(txtHipsB4.Text);
        busObject.RightThighB4 = double.Parse(txtRightThighB4.Text);
        busObject.LeftThighB4 = double.Parse(txtLeftThighB4.Text);
        busObject.RightArmB4 = double.Parse(txtRightArmB4.Text);
        busObject.LeftArmB4 = double.Parse(txtLeftArmB4.Text);

        //call method to save input data
        busObject.SaveB4Data();

        //clear text boxes of data
        this.txtChestB4.Clear();
        this.txtWaistB4.Clear();
        this.txtHipsB4.Clear();
        this.txtRightThighB4.Clear();
        this.txtLeftThighB4.Clear();
        this.txtRightArmB4.Clear();
        this.txtLeftArmB4.Clear();

        //close form
        this.Close();
    }

以下是MeasurementsBOL类的两个属性。虽然我没有显示它，但该对象已被实例化：

//properties for variables
public double BodyFatB4 
{
    get { return bodyFatB4; }
    set { bodyFatB4 = nutritionObject.BodyFatStart;}
}

public double BodyWeightB4 
{ 
    get { return bodyWeightB4; }
    set { bodyWeightB4 = nutritionObject.BodyWeight; }
}

Answer 1

此代码不在任何方法，构造函数等中：

private MeasurementsBOL busObject = new MeasurementsBOL();

//autofill bodyfat and body weight from nutrition form when form opens
busObject.BodyFatB4 = double.Parse(lblBodyFatB4FromNutrition.Text);
busObject.BodyWeightB4 = double.Parse(lblWeightB4FromNutrition.Text);

有一个变量声明很好，但你不能只添加那样的额外语句。幸运的是，您可以使用object initializer：

private MeasurementsBOL busObject = new MeasurementsBOL()
{
    BodyFatB4 = double.Parse(lblBodyFatB4FromNutrition.Text),
    BodyWeightB4 = double.Parse(lblWeightB4FromNutrition.Text)
};

基本上，类型只能包含诸如字段声明，构造函数声明，属性声明，方法声明等成员。它不能只包含语句。

使用其他类的属性与实例混淆

1 个答案: