textbox not aligning in a table cell

I have created a table with Layout->Insert Table. in Visual Studio. There are 4 rows and 4 columns in the table. Now I want to put a textbox of a size greater than the size of the cell . What do I do to automatically adjust the size of the cell to the size of the textbox and also align the textbox to the centre of the cell ?

Please help

Regards

Sanjish 

 

 
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