请问为什么矩阵乘法运算代码有些bug？

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void ReadMatrix(ref float[,] maxtrix, TextBox tb)
        {
            string tpstr;
            string[] tpstrs;

            //读取A矩阵
            tpstr = textBox1.Lines[0];
            tpstrs = tpstr.Split(',');        //以‘，’为分割

            maxtrix = new float[tb.Lines.Length, tpstrs.Length];

            for (int i = 0; i < textBox1.Lines.Length; i++)
            {
                tpstr = tb.Lines[i];
                tpstrs = tpstr.Split(',');

                for (int j = 0; j < tpstrs.Length; j++)
                {
                    maxtrix[i, j] = Convert.ToSingle(tpstrs[j]);
                }
            }
        }

private void button3_Click(object sender, EventArgs e)
        {
            float[,] A, B, C;
            A = new float[1, 1];
            B = new float[1, 1];

            ReadMatrix(ref A, textBox1);
            ReadMatrix(ref B, textBox2);

            C = new float[A.GetLength(0), B.GetLength(1)];

            for (int i = 0; i < A.GetLength(0); i++)
            {
                for (int j = 0; j < B.GetLength(1); j++)
                {
                    for (int k = 0; k < A.GetLength(1); k++)
                    {
                        C[i, j] = C[i, j] + (A[i, k] * B[k, j]);

                    }
                    textBox3.Text = textBox3.Text + C[i, j].ToString() + ",";
                }
                textBox3.Text = textBox3.Text + "\n";
            }
        }

输出结果：

你的逗号后面是不是还有多余的空格，造成数据没有读取到