通过单元测试调用时,DataGridView不接受DataSource

Question

通过UI调用时代码工作正常,但通过单元测试调用时不起作用.我能够为简单的Winform App重新编写这个.

namespace WinFormApp
{
    public class Pair
    {
        public string Key { get; set; }
        public string Value { get; set; }
    }

    public class FormManager
    {
        List<Pair> _source = new List<Pair>()
        {
            new Pair() { Key="1", Value = "one" },
            new Pair() { Key = "2", Value = "two" }
        };

        public FormManager(DataGridView dgv)
        {
            dgv.DataSource = _source;
        }
    }

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            FormManager manager = new FormManager(dataGridView1); // This works
        }
    }
}

单元测试代码

namespace WinFormApp.Test
{
    [TestClass()]
    public class FormManagerTest
    {
        private DataGridView dataGridView1;

        [TestMethod()]
        public void FormManagerTestSource()
        {
            this.dataGridView1 = new System.Windows.Forms.DataGridView();

            FormManager target = new FormManager(dataGridView1);

            Assert.AreEqual(2, dataGridView1.Rows.Count); // This fails.
        }
    }
}

以下代码由设计人员生成

private void InitializeComponent()
{
    this.dataGridView1 = new System.Windows.Forms.DataGridView();
    ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).BeginInit();
    this.SuspendLayout();
    // 
    // dataGridView1
    // 
    this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
    this.dataGridView1.Location = new System.Drawing.Point(20, 27);
    this.dataGridView1.Name = "dataGridView1";
    this.dataGridView1.Size = new System.Drawing.Size(240, 150);
    this.dataGridView1.TabIndex = 0;
    // 
    // Form1
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.ClientSize = new System.Drawing.Size(284, 262);
    this.Controls.Add(this.dataGridView1);
    this.Name = "Form1";
    this.Text = "Form1";
    ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).EndInit();
    this.ResumeLayout(false);

}

我的猜测是我在单元测试代码路径中缺少对dataGridView1对象的某种init调用.但是在单元测试中使用设计器生成的代码并没有帮助.这与与对象关联的实际对象有关Form吗？

Answer 1

添加dataGridView1.BindingContext = new BindingContext();使这工作.这个答案有帮助. 数据绑定不在Form.Controls集合中的DataGridView控件？

[TestMethod()]
public void FormManagerTestSource()
{
    this.dataGridView1 = new System.Windows.Forms.DataGridView();
    FormManager target = new FormManager(dataGridView1);
    Assert.AreEqual(0, dataGridView1.Rows.Count); // 0 initially.
    dataGridView1.BindingContext = new BindingContext(); // this makes it work.
    Assert.AreEqual(2, dataGridView1.Rows.Count); // 2 as expected.
}