c# - 如何将值从子窗体传递到父窗体？

Question

我有 2 个表单，分别是 BillingForm(父表单)和 SearchProduct(子表单)。

BillingForm代码

private void textBoxProductNo_KeyDown(object sender, KeyEventArgs e)
{
    if(e.KeyCode==Keys.F9)
    {
        using(SearchProduct sp=new SearchProduct)
        {
            sp.ShowDialog(this);
        }
    }
}

public void updatedText(string fromChildForm)
{
     textBoxProduct.text=fromChildForm;
}

SearchProduct表单代码(子表单)

private void dataGridView1_KeyDown(object sender,KeyEventArgs e)
{
    if(e.KeyCode==Keys.Enter)
    {
        BillingForm bf=(BillingForm)this.Owner;   //Error appear here 
        bf.updatedText("Hello World");
        this.close();
    }
}

我收到一条错误消息。

BillingSoftware.exe 中出现类型为“System.InvalidCastException”的未处理异常
附加信息:无法将“BillingForm.MDIParent”类型的对象转换为类型“BillingForm.BillingForm”

Answer 1

尝试将父级传递给构造函数并在变量中使用它

using(SearchProduct sp = new SearchProduct(this))
{
    sp.ShowDialog(this);
}

//In SearchProduct class
public BillingForm MyParent {get; private set;}

public SearchProduct(BillingForm parent)
{
    this.MyParent = parent;
}

private void dataGridView1_KeyDown(object sender,KeyEventArgs e)
{
    if (e.KeyCode == Keys.Enter)
    {
        BillingForm bf = this.MyParent;
        bf.updatedText("Hello World");
        this.close();
    }
}