本文介绍了检查文本框为空,并返回消息框?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我说这句话,以检查是否文本框为空,但在MessageBox总是显示了
羯羊文本框为空或不是。

 私人无效NextButton_Click(对象发件人,EventArgs五)
{
十进制MarkPoints,X,Y;
X = HoursNumericUpDown.Value;
Y = MarkNumericUpDown.Value;
MarkPoints = X * Y;

//十进制MarkPoints =(十进制)HoursNumericUpDown.Value *(十进制)HoursNumericUpDown.Value;


的DataGridViewRow dgvRow =新的DataGridViewRow();
DataGridViewTextBoxCell dgvCell =新DataGridViewTextBoxCell();

dgvCell =新DataGridViewTextBoxCell();
dgvCell.Value = MaterialTextBox.Text;
dgvRow.Cells.Add(dgvCell);

dgvCell =新DataGridViewTextBoxCell();
dgvCell.Value = HoursNumericUpDown.Value;
dgvRow.Cells.Add(dgvCell);

dgvCell =新DataGridViewTextBoxCell();
dgvCell.Value = MarkNumericUpDown.Value;
dgvRow.Cells.Add(dgvCell);

dgvCell =新DataGridViewTextBoxCell();
dgvCell.Value = MarkPoints;
dgvRow.Cells.Add(dgvCell);

dataGridView1.Rows.Add(dgvRow);

MaterialTextBox.Clear();
HoursNumericUpDown.Value = HoursNumericUpDown.Minimum;
MarkNumericUpDown.Value = MarkNumericUpDown.Minimum;

如果(String.IsNullOrEmpty(MaterialTextBox.Text))
{
MessageBox.Show(输入物料名称请,错误,MessageBoxButtons.OK,MessageBoxIcon。警告);
//dataGridView1.Rows.Clear();
}
,否则
{
/ *如果(MarkNumericUpDown.Value< 50)
{
INT指数= dataGridView1.Rows.Add();
dataGridView1.Rows [1] .Cells [4]。价值=F;
}
,否则如果(MarkNumericUpDown.Value大于50&安培;&安培; MarkNumericUpDown.Value< = 64)
{
dataGridView1.Rows [指数] .Cells [4] .value的=F;
} * /


解决方案

试试这个条件,而不是

 如果(string.IsNullOrWhiteSpace(MaterialTextBox.Text)){
//消息框
}

这会照顾一些字符串只包含空格字符,你不会要处理的字符串相等有时可能会非常棘手。


I made this statement to check if TextBox is empty, but the MessageBox always shows upwether the TextBox is empty or not.

    private void NextButton_Click(object sender, EventArgs e)
    {
        decimal MarkPoints, x, y;
        x = HoursNumericUpDown.Value;
        y = MarkNumericUpDown.Value;
        MarkPoints = x * y;

        //decimal MarkPoints = (decimal)HoursNumericUpDown.Value * (decimal)HoursNumericUpDown.Value;


        DataGridViewRow dgvRow = new DataGridViewRow();
        DataGridViewTextBoxCell dgvCell =  new DataGridViewTextBoxCell();

        dgvCell = new DataGridViewTextBoxCell();
        dgvCell.Value = MaterialTextBox.Text;
        dgvRow.Cells.Add(dgvCell);

        dgvCell = new DataGridViewTextBoxCell();
        dgvCell.Value = HoursNumericUpDown.Value;
        dgvRow.Cells.Add(dgvCell);

        dgvCell = new DataGridViewTextBoxCell();
        dgvCell.Value = MarkNumericUpDown.Value;
        dgvRow.Cells.Add(dgvCell);

        dgvCell = new DataGridViewTextBoxCell();
        dgvCell.Value = MarkPoints;
        dgvRow.Cells.Add(dgvCell);

        dataGridView1.Rows.Add(dgvRow);

        MaterialTextBox.Clear();
        HoursNumericUpDown.Value = HoursNumericUpDown.Minimum;
        MarkNumericUpDown.Value = MarkNumericUpDown.Minimum;

        if (String.IsNullOrEmpty(MaterialTextBox.Text))
        {
            MessageBox.Show("Enter Material Name Please.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            //dataGridView1.Rows.Clear();
        }
        else
        {
            /*if (MarkNumericUpDown.Value < 50)
            {
                int index = dataGridView1.Rows.Add();
                dataGridView1.Rows[1].Cells[4].Value = "F";
            }
            else if (MarkNumericUpDown.Value > 50 && MarkNumericUpDown.Value <= 64)
            {
                dataGridView1.Rows[index].Cells[4].Value = "F";
            }*/
解决方案

Try this condition instead:

if (string.IsNullOrWhiteSpace(MaterialTextBox.Text)) {
    // Message box
}

This will take care of some strings that only contain whitespace characters and you won't have to deal with string equality which can sometimes be tricky

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08-19 20:20
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