Если текстбокс пустой то ошибка

I made this statement to check if TextBox is empty, but the MessageBox always shows up
wether 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";
            }*/

Try doing the following

if (String.IsNullOrEmpty(MaterialTextBox.Text) || String.IsNullOrWhiteSpace(MaterialTextBox.Text))
    {
        //do job
    }
    else
    {
        MessageBox.Show("Please enter correct path");
    }

Hope it helps

answered Nov 28, 2016 at 5:44

if (MaterialTextBox.Text.length==0)
{
message

}

answered Jul 30, 2013 at 9:44

For multiple text boxes — add them into a list and show all errors into 1 messagebox.

// Append errors into 1 Message Box      

 List<string> errors = new List<string>();   

 if (string.IsNullOrEmpty(textBox1.Text))
    {
        errors.Add("User");
    }

    if (string.IsNullOrEmpty(textBox2.Text))
    {
        errors.Add("Document Ref Code");
    }

    if (errors.Count > 0)
    {
        errors.Insert(0, "The following fields are empty:");
        string message = string.Join(Environment.NewLine, errors);
        MessageBox.Show(message, "errors", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        return;
    } 

answered May 15, 2020 at 12:27

Becasue is a TextBox already initialized would be better to control if there is something in there outside the empty string (which is no null or empty string I am afraid). What I did is just check is there is something different than «», if so do the thing:

 if (TextBox.Text != "") //Something different than ""?
        {
            //Do your stuff
        }
 else
        {
            //Do NOT do your stuff
        }

answered Jul 22, 2020 at 12:58

I’m trying to validate a text box in a form to not having empty string if the user didn’t entered anything in the text box, so if the text box was empty, the user has to enter a value ,and my code was like this, but it is not working

  public int TextBox_Validation(string sender)
  {


      try
      {

          if (string.IsNullOrEmpty(sender))
          {
              MessageBox.Show("Please enter a value");
          }

      }
      catch
      {
          int num = int.Parse(sender);
          return 0;

      }
      return 0;
  }

public bool TextBox_Validation(string sender) {
        return !string.IsNullOrEmpty(sender);
}

        if(TextBox_Validation(textbox1.Value)) {
             //OK
         } else { 
            MessageBox.Show("Please enter a value");
             //ETC
        }

answered Jun 9, 2011 at 18:42

You aren’t throwing an exception so you won’t make it into the catch block.

public int TextBox_Validation(string value)
{
    int integer = 0;

    if( string.IsNullOrEmpty( value ) )
    {
        MessageBox.Show( "Please enter a value" );    
    }
    else
    {
        int.TryParse( value, out integer );
    }

    return integer;
}

answered Jun 9, 2011 at 18:42

You’re algorithm is incorrect. The catch block is used to catch errors that occur within the preceeding try block. In this case, I don’t see a runtime error occurring so there probably is no need to a try/catch block, but I’ll leave in for example sake. Also, your function doesn’t provide a way for the program to know if it was empty or not. You could return 0 if it is empty or 1 if not. or return boolean true or false. Maybe a function like this would be better:

  public bool TextBox_Validation(string sender)
  {
      try
      {

          if (string.IsNullOrEmpty(sender))
          {
              MessageBox.Show("Please enter a value");
              return false;
          }
          else
              return true;

      }
      catch(Exception ex)
      {
          MessageBox.Show(ex.Message);
          return false;
      }
  }

answered Jun 9, 2011 at 18:43

You can try something like this instead

if (String.IsNullOrEmpty(txtTextBox.Text))
    {
        MessageBox.Show("Enter Value Please.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);           
    }
    else
    {
//whatever u need to do
    }

answered Jun 9, 2011 at 18:43

answered Jun 9, 2011 at 18:43

I’m trying to validate a text box in a form to not having empty string if the user didn’t entered anything in the text box, so if the text box was empty, the user has to enter a value ,and my code was like this, but it is not working

  public int TextBox_Validation(string sender)
  {


      try
      {

          if (string.IsNullOrEmpty(sender))
          {
              MessageBox.Show("Please enter a value");
          }

      }
      catch
      {
          int num = int.Parse(sender);
          return 0;

      }
      return 0;
  }

public bool TextBox_Validation(string sender) {
        return !string.IsNullOrEmpty(sender);
}

        if(TextBox_Validation(textbox1.Value)) {
             //OK
         } else { 
            MessageBox.Show("Please enter a value");
             //ETC
        }

answered Jun 9, 2011 at 18:42

You aren’t throwing an exception so you won’t make it into the catch block.

public int TextBox_Validation(string value)
{
    int integer = 0;

    if( string.IsNullOrEmpty( value ) )
    {
        MessageBox.Show( "Please enter a value" );    
    }
    else
    {
        int.TryParse( value, out integer );
    }

    return integer;
}

answered Jun 9, 2011 at 18:42

You’re algorithm is incorrect. The catch block is used to catch errors that occur within the preceeding try block. In this case, I don’t see a runtime error occurring so there probably is no need to a try/catch block, but I’ll leave in for example sake. Also, your function doesn’t provide a way for the program to know if it was empty or not. You could return 0 if it is empty or 1 if not. or return boolean true or false. Maybe a function like this would be better:

  public bool TextBox_Validation(string sender)
  {
      try
      {

          if (string.IsNullOrEmpty(sender))
          {
              MessageBox.Show("Please enter a value");
              return false;
          }
          else
              return true;

      }
      catch(Exception ex)
      {
          MessageBox.Show(ex.Message);
          return false;
      }
  }

answered Jun 9, 2011 at 18:43

You can try something like this instead

if (String.IsNullOrEmpty(txtTextBox.Text))
    {
        MessageBox.Show("Enter Value Please.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);           
    }
    else
    {
//whatever u need to do
    }

answered Jun 9, 2011 at 18:43

answered Jun 9, 2011 at 18:43

On a site I found the TryParse method (how to check if there is a empty textbox in C#) but I don’t know how to use it.

int outputValue=0;
bool isNumber=false;
isNumber=int.TryParse(textBox1.Text, out outputValue); 
if(!isNumber)
{
 MessageBox.Show("Type numbers in the textboxes");
}
else
{
// some code
}

and how can i solve this for 1+ number of textboxes

Many ways to complete this task

1. string.IsNullOrEmpty(textbox1.Text)  
2. textbox1.Text =    string.empty();  
3. textbox1.Text = "";

answered Jul 3, 2014 at 6:56

You can try this:

if(textBox1.Text.length==0) {
  //do something
 }

answered Apr 20, 2020 at 16:26

On a site I found the TryParse method (how to check if there is a empty textbox in C#) but I don’t know how to use it.

int outputValue=0;
bool isNumber=false;
isNumber=int.TryParse(textBox1.Text, out outputValue); 
if(!isNumber)
{
 MessageBox.Show("Type numbers in the textboxes");
}
else
{
// some code
}

and how can i solve this for 1+ number of textboxes

Many ways to complete this task

1. string.IsNullOrEmpty(textbox1.Text)  
2. textbox1.Text =    string.empty();  
3. textbox1.Text = "";

answered Jul 3, 2014 at 6:56

You can try this:

if(textBox1.Text.length==0) {
  //do something
 }

answered Apr 20, 2020 at 16:26